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Are predictors of future suicide attempts and the transition from suicidal ideation to suicide attempts shared or distinct: A 12-month prospective study among patients with depressive disorders
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Are predictors of future suicide attempts and the transition from suicidal ideation to suicide attempts shared or distinct: A 12 - month prospective study among patients with depressive disorders. Lai Fong Chan, Shamsul Azhar Shah, Maniam Thambu www.elsevier.com/locate/psychres
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Psychiatry Research
Received date: 12 May 2014 Revised date: 13 August 2014 Accepted date: 26 August 2014 Cite this article as: Lai Fong Chan, Shamsul Azhar Shah, Maniam Thambu, Are predictors of future suicide attempts and the transition from suicidal ideation to suicide attempts shared or distinct: A 12 - month prospective study among patients with depressive disorders., Psychiatry Research, http://dx.doi.org/10.1016/ j.psychres.2014.08.055 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Are predictors of future suicide attempts and the transition from suicidal ideation to suicide attempts shared or distinct: A 12 - month prospective study among patients with depressive disorders. Lai Fong Chana*, Shamsul Azhar Shahb, Maniam Thambua Dept. of Psychiatrya & Dept. of Community Medicineb, National University of Malaysia Medical Centre (UKMMC), Kuala Lumpur, Malaysia
*Corresponding author: Dr. Lai Fong Chan Associate Professor & Consultant Psychiatrist Department of Psychiatry Universiti Kebangsaan Malaysia Medical Centre (UKMMC) Jalan Yaacob Latif Bandar Tun Razak Cheras, 56000 Kuala Lumpur, Malaysia Tel no: +60391456143 Fax no: +60391456681 Email address: [email protected]
ABSTRACT Our study aimed to examine the interplay between clinical and social predictors of future suicide attempt and the transition from suicidal ideation to suicide attempt in depressive disorders. Sixty-six Malaysian inpatients with a depressive disorder were assessed at index admission and within 1 year for suicide attempt, suicidal ideation, depression severity, life event changes, treatment history and relevant clinical and sociodemographic factors.
One-fifth of suicidal ideators transitioned to a future suicide
attempt. All future attempters (12/66) had prior ideation and 83% of attempters had a prior attempt. The highest risk for transitioning from ideation to attempt was 5 months post-discharge. Single predictor models showed that previous psychiatric hospitalization and ideation severity were shared predictors of future attempt and ideation to attempt transition. Substance use disorders (especially alcohol) predicted future attempt and approached significance for the transition process. Low socio-economic status predicted the transition process while major personal injury/illness predicted future suicide attempt. Past suicide attempt, subjective depression severity and medication compliance predicted only future suicide attempt. The absence of prior suicide attempt did not eliminate the risk of future attempt. Given the limited sample, future larger studies on mechanisms underlying the interactions of such predictors are needed.
Key words: future suicide attempt, transition ideation to attempt, clinical & social predictors
1. Introduction Suicide is a leading cause of death worldwide (Mathers et al., 2006). Morbidity due to self-harm including suicide attempts has increased dramatically by 136% within the past decade (Institute for Health Metrics and Evaluation, 2013). One of the key processes in the prevention of suicidal behavior involves the accurate identification of those who are at highest risk of suicidal acts (attempted or completed suicide). Such highrisk populations have been identified among inpatients with depressive disorders (Bostwick, and Pankratz, 2003). Prospective studies in patients with unipolar and bipolar depression have demonstrated the following predictive risk factors for future suicidal acts: past suicide attempts, duration spent in major depressive episodes, lack of a partner (Sokero et al., 2005); severity of subjective rating of depression, cigarette smoking (Oquendo et al., 2004), alcohol use disorders (Oquendo et al., 2006); younger onset of illness, bipolar diagnosis and psychiatric hospitalizations (Tondo et al., 2007). The role of suicidal ideation as a risk factor for more serious suicidal acts has been somewhat mixed in the literature. Busch et al.’s (2003) retrospective chart review found that only 39% of patients, mostly depressed, who eventually committed suicide had endorsed suicidal ideation a week before committing suicide (8). A more recent review by Mendez-Bustos et al. (2003) found that greater suicidal ideation was significantly associated with re-attempted suicide. The evaluation of suicidal ideation is crucial in suicidal risk assessment as it can be viewed as the gateway to more serious suicidal acts. Large et al. (2013) highlighted the challenge of predicting who among those with suicidal ideation will eventually complete suicide, partly due to the non-specificity of wellestablished risk factors of suicidal behavior. Although there is a growing body of
literature that has examined the differences between suicidal ideators and attempters cross-sectionally (Klonsky et al., 2014), an important knowledge gap still exists with regards to understanding the critical transition from suicidal ideation to attempts. Retrospective, population-based studies have shown that prior suicidal behaviours i.e. previous plans, earlier onset of ideation onset (ten Have et al., 2013) and psychiatric disorders such as substance, bipolar, conduct and post-traumatic stress disorders predicted the transition from ideation to plans and attempts (Nock et al., 2010). Yang et al’s (2014) prospective study among Chinese medical students demonstrated the following transition risk factors: history of suicidal behavior in first-degree relatives, severe anxiety symptoms, impulsivity, physical abuse and parental divorce. The conundrum that most clinicians face is to identify which suicidal ideator will eventually attempt suicide. Such a decision carries important implications on the intensiveness of management and utilization of resources in mental health services i.e. outpatient versus inpatient treatment. May et al.’s (2012) prospective study among 49 patients with depressive disorders demonstrated that cluster B personality disorders independently predicted future suicide attempts from ideators after accounting for the most robust predictor from existing literature, a history of past attempt. Apart from that study, the evidence-base for risk assessment of depressed patients progressing from suicidal ideation to attempts is still scarce, more so among non-Western populations. Another crucial clinical question that needs to be addressed is whether predictors of future attempts are distinct or overlap with predictors of the transition from ideation to attempts.
Aims of the study Our aim in this study was to examine the interplay between clinical and social predictors of (i) future suicide attempt and (ii) the transition from suicidal ideation to suicide attempt among patients with depressive disorders in a Malaysian sample.
2. Methods
2.1 Participants and procedures In this paper, we report the prospective data from a 1-year longitudinal naturalistic cohort of patients admitted to the psychiatric wards of the National University of Malaysia Medical Centre (UKMMC), a tertiary-level, teaching hospital in Kuala Lumpur, the capital city situated in Peninsular Malaysia. Malaysia is an upper middle income South East Asian nation with an ethnic composition (Peninsular Malaysia) of Malays (63.1%), Chinese (24.6%), Indians (7.3%), indigenous groups (4.3%) and others (0.7%) (Department of Statistics, Malaysia, 2011). This study was approved by the Research and Ethics Committee of the National University of Malaysia Medical Centre and registered with the National Medical Research Register of Malaysia (NMRR ID No: NMRR-12-1082-14456). A hundred and thirty three consecutive psychiatric inpatients were screened for study recruitment from May 2007 to October 2008. One hundred and sixteen patients met eligibility criteria: 18 to 76 years of age; diagnosed with a depressive disorder according to DSM-IV-TR; able to comprehend English or Malay (the national language of Malaysia) and were not too ill or psychotic to undergo study assessments. Seventy-five patients gave written informed consent and completed a baseline evaluation within 72
hours of admission. A diagnosis of depressive disorder was confirmed with the Structured Clinical Interview for DSM-IV Axis I Disorders, Clinician Version (SCID I/CV), (First et al. 1997). A comprehensive clinical interview during SCID–I/CV administration was done together with other interviewer-rated and self-report questionnaires detailed below. Study participants were interviewed in a room where privacy and confidentiality were assured. The interviews were conducted by a masterslevel psychiatric resident (LFC) trained and supervised by a senior consultant psychiatrist (MT) during the course of the study in the usage of study instruments. Data collected included socio-demographic and clinical factors such as the presence or absence of suicidal ideation, suicide attempt (current and previous), severity of suicidal ideation and depression, previous history of psychiatric hospitalization, psychotic or melancholic features, co-morbid substance use and medical conditions, treatment history (medication compliance, ECT), history of sexual abuse, family history of attempted or completed suicide and recent life event changes. At baseline, participants were mostly female (56%), married (66.7%) and below middle social class (62.7%). Participants’ age ranged from 18-76 years with a mean of 43.8 years (s.d.=12.1). Ethnic composition was consistent with the hospital service utilization demographics of an urban Malaysian population but somewhat different from the general population: Chinese (40%) of whom 46.6% were Christians and 53.3% were Buddhists-Taoists; Malays (37.3%) who were exclusively Muslim, and Indians (22.7%) who were predominantly Hindus (82.4%). In terms of treatment, 32% of cases were on at least 1 mood-stabiliser and 67% were on at least 1 antidepressant (SSRI/SNRI) while 13.6% received ECT treatment. Further details on clinical and socio-demographic characteristics have been reported elsewhere (Chan et
al. 2011; Chan et al., 2012). Study participants were assessed at baseline and followed-up within 12 months from baseline. Follow-up data was available for 66 participants, including 89% of baseline suicidal ideators (50/56) (Figure 1). All interviews were conducted in person except for 6 patients over the phone. Socio-demographic and clinical characteristics of the 9 patients that were lost to follow-up (12 % attrition rate) did not differ significantly from the 66 participants assessed longitudinally except for having a lower baseline median SSI score by 5 points (p<0.05).
2.2 Measures 2.2.1 Suicidal behaviour Suicidal behavior was assessed from the clinical interview and psychiatric records. A suicide attempt was coded as having occurred in the past prior to baseline, at baseline as part of the SCID and in future after baseline during the follow-up assessment in the event of any act of self-harm with inferred or explicit intent to (4, 5, 18). Suicidal ideation was determined as present at baseline and in the future after baseline if the patient had the thought or intention of attempting suicide from clinical interview. The severity of suicidal ideation was evaluated with the Scale for Suicidal ideation (SSI), an interviewer-administered rating scale with adequate convergent and construct and validity as well as Cronbach coefficient alpha ranging from 0.84 to 0.89 among psychiatric inpatients (Beck et al. 1979).
2.2.2 Diagnostic, clinical and psychosocial variables The SCID – I/CV was used for Axis I depressive disorder diagnoses including comorbid anxiety disorders and substance use disorders as well as assessment of the following clinical variables: psychotic or melancholic features, previous history of psychiatric hospitalization, medication and ECT treatment, history of sexual abuse and family history of attempted or completed suicide. The severity of depression in the past one week of assessment was evaluated at baseline and follow-up with the national language (Malay) version of the 21-item Beck Depression Inventory (BDI) (Cronbach’s alpha=0.965) (Chan et al. 2011). The Malay version of the Social Readjustment Rating Scale (SRRS) assessed patients’ self-report on the magnitude of life event changes within the past 12 months of assessment at baseline and follow-up. The original English SRRS demonstrated good concordance (Spearman's rho: 0.97 to 0.91) between Malaysian and American samples in terms of the order of magnitude to changes in life events (20). This Malay version of the SRRS was modified with permission from a Malay version translated by Othman (1986), including the addition of 20 questions that Othman had excluded from the original SRRS. This author and Othman both used the back-translation technique. Assessment of compliance was based on participants’ self-report of not missing more than 30% of prescribed medication (Scott, 2000) within the period of baseline and follow-up assessment. Socio-demographic data included age, gender, marital status, ethnicity, religion, employment status, educational level and social class based on occupational status according to the National Readership Survey (NRS) social grade, United Kingdom.
2.3 Statistical analysis Data was analysed using the Statistical Package for the Social Sciences (SPSS) software, version 21. Univariate analysis was performed with simple logistic regression for categorical independent variables. Two dependent variables were analysed as dichotomous (yes/no) variables: (i) future suicide attempt in the total sample population (with and without baseline suicidal ideation) and (ii) future suicide attempt among baseline suicidal ideators (transition from ideation to attempt). The following variables were analysed as dichotomous independent variables: gender, marital status, social class (middle class and above/below middle class), education (high school and above/lower than high school), employment, suicidal ideation, past and baseline suicide attempt, psychotic or melancholic features, previous history of psychiatric hospitalization, medication and ECT treatment, medication compliance, chronic medical condition, history of sexual abuse, family history of attempted or completed suicide and each of the 43 items of change in live events in the SRSS (present/absent). Other categorical independent variables included: ethnicity, religion, and diagnoses of depressive, anxiety and substance disorders. The following baseline independent variables were analysed as continuous scores: age (independent t-test), severity of depression (BDI) (independent ttest), severity of suicidal ideation (SSI) (Mann Whitney test), magnitude of life event changes (SRSS) (Mann Whitney test). Significant independent variables from univariate analysis (p<0.05) were entered into multivariate logistic regression models using the forward conditional method to determine the independent predictive risk factors for (i) future suicide attempt in the total sample population (with and without baseline suicidal ideation) and (ii) future suicide attempt among baseline suicidal ideators (transition from
ideation to attempt). Kaplan-Meier survival analysis was used to estimate the highest risk of future suicide attempt. 3. Results
3.1 Description of suicidal behaviour Twelve out of 66 patients (18.2%) had made at least one suicide attempt during the 1-year follow-up period, all of which had baseline suicidal ideation. Thirty percent (9/30) of patients with a past suicide attempt prior to baseline, and 28.8% (5/19) with an index suicide attempt at baseline reattempted suicide within a year. Twenty four percent of baseline suicidal ideators (12/50) subsequently attempted suicide. Seventeen percent (2/12) of future suicide attempters did not have any history of suicide attempt prior to or at baseline.
3.2 Period of highest risk of suicide attempt From the Kaplan-Meier survival analysis, 9 out of the 12 future suicide attempts (75%) occurred within 149 days (5 months) post-discharge, after which the rate dropped significantly (Figure 2). Therefore, the period of highest risk of a subsequent suicide attempt is estimated to be within 5 months after hospital discharge. Survival analysis for the transition from ideation to attempt is similar because all future attempts were preceded by baseline suicidal ideation.
3.3 Risk factors for future suicide attempt Univariate analysis from simple logistic regression found the following factors to be significantly associated with future suicide attempt: previous psychiatric hospitalization (p=0.02, OR=13.75, 95%CI=1.66-114.13), past suicide attempt prior to baseline assessment (p=0.03, OR=4.71, 95%CI=1.14-19.44), history of alcohol dependence (p=0.04, OR=7, 95% CI=1.14-42.97), any type of substance use disorder i.e. alcohol, nicotine, amphetamine, opioid or benzodiazepine (p=0.01, OR=6, 95% CI=1.45-24.92), severity of suicidal ideation at baseline (higher baseline SSI total score) (p<0.01, U=136, z=-3.132), severity of subjective ratings of depression at baseline (higher baseline BDI total score) (p=0.02, t = -2.370, d.f. = 31.52) and the presence of major personal injury or illness from baseline SRRS (p=0.03, OR=4.9, 95% CI=1.08-22.23). Compliance to medication was found to be a protective factor against future suicide attempt (p=0.01; OR=0.12; 95%CI=0.02-0.62) (Table 1). A multivariate logistic regression model, which included factors from univariate analysis with p<0.05 showed that previous psychiatric hospitalization was the strongest predictor of a future suicide attempt (B=2.93, p=0.01, OR=18.76, 95%CI=1.88-187.71) followed by any type of substance use disorder (B=2.06, p=0.02, OR=7.82, 95% CI=1.50-40.79) (Table 3). The presence of major personal injury or illness from baseline SRRS approached a trend towards significance (B=2.10, p=0.05, OR=8.15, 95%CI=1.0 - 66.46). The sensitivity, specificity and area under the ROC curve (AUC) for this multivariate model are as follows: sensitivity=75%, specificity=83.3% and AUC=0.87.
3.4 Risk factors for transition of suicidal ideation to attempt Univariate analysis from binary logistic regression showed the following factors to be significantly associated with future suicide attempt among baseline suicide ideators: low social class (below middle class) (p=0.046, OR=8.91, 95%CI=1.04-76.04), previous psychiatric hospitalization (p=0.01, OR=15.13, 95%CI=1.77-129.33), and severity of suicidal ideation at baseline (higher baseline SSI total median scores) (p=0.03; OR=1.10; 95%CI=1.01-1.20). The presence of any type of substance use disorder (alcohol, nicotine, amphetamine, opioid or benzodiazepine) showed a trend towards significance (p=0.06; OR=4.13; 95% CI=0.96-17.70) (Table 2). No individual items of change in life events from the SRRS were significant factors. A multivariate logistic regression model which included factors from univariate analysis with p<0.05 showed that previous psychiatric hospitalization was the strongest predictor of the transition from baseline suicidal ideation to future suicide attempt (B=2.87, p=0.005, OR=57.702, (95%C.I.=3.3171003.706) followed by low social class (B=2.39, p=0.04, OR=10.85, (95%CI=1.15102.31) (Table 3). The sensitivity, specificity and area under the ROC curve (AUC) for this multivariate model are as follows: sensitivity=83.3%, specificity=78.9% and AUC=0.84.
4. Discussion We found that 24% of suicidal ideators progressed to attempted suicide among inpatients with depressive disorders. This finding was comparable to May et al.’s (2012) figure of 26.5%. Our finding that the rate of suicide attempts, including the transition from ideation to attempt was highest within the 5-month post-discharge period concurs
with Oquendo et al. (2004) which showed that the period of highest risk for future suicidal acts was within the first year after discharge.
4.1 Clinical risk factors. Previous psychiatric hospitalization has been established as a common risk factor for attempted suicide (Beautrais, 2001), especially in mood disorders (Botswick and Pankratz, 2000; Angst et al, 2002). We replicated this finding in terms of future suicide attempts and the transition from ideation to attempt in our univariate analysis. In fact, previous psychiatric hospitalization emerged as the strongest predictor that differentiated between suicidal ideators who progressed to a future attempt from those who did not attempt, as well as for future attempts in general. Patients’ subjective ratings of baseline depression severity during index admission were significantly associated with a future suicide attempt from univariate but not multivariate analysis. However, depression severity was not shown to be significantly associated with the transition from ideation to attempt even in the univariate analysis. A history of previous psychiatric hospitalization may be more representative of objective severity and functional impairment with a higher impact on the progression from ideation to attempt over a longitudinal course of illness compared to an acute subjective rating of depression. Also, the decision to hospitalize a depressed patient is often based on the clinical assessment of the level of suicidal risk in each individual case (Botswick and Pankratz, 2000). As expected, past suicide attempt prior to baseline was a predictor of a future attempt from our univariate analysis. However, this was not shown to be an independent predictor of future suicide attempt. This is a departure from the well-replicated finding
that past attempt is one of the most robust predictors of future attempt. On top of that, past suicide attempt did not predict the transition from ideation to attempt even in the univariate analysis. This is possibly because of a type II error due to the limitation of our sample size. Nevertheless, the absence of past suicide attempt does not negate the risk of a future suicide attempt as a substantial minority (16.7%) of future suicide attempters did not have any prior attempts. Compliance to medication (mainly antidepressants e.g. SSRIs/SNRIs) was protective against future suicide attempts in the univariate analysis. This is an important finding as there is a current lack of direct evidence that supports the role of antidepressant adherence in reducing rather than increasing future suicidal acts (Woldu et al, 2011). However, this association failed to remain significant in multivariate analysis for future attempt and was not significantly associated with the transition process in the univariate analysis either, highlighting the need for further studies in this area with larger sample size. Our study showed that any type of substance use disorder was significantly associated with future attempt. The association with the transition from ideation to attempt also approached significance in single predictor models. Specifically, a history of alcohol dependence predicted future attempts in univariate analysis. This concurs with previous longitudinal studies that has highlighted the role of comorbid substance disorders as a significant risk factor for suicidal behaviour in mood disorders, both in population-based (Bolton et al, 2011) and clinical samples, especially alcohol (Maser et al, 2002).
Several lines of evidence from previous research point towards impulsivity as a possible mechanism underlying the role of substance disorders in leading to future suicide attempts, in particular, the pathway of transitioning from ideation to attempt. Population studies have demonstrated that impulse-control disorders in probands (Nock et al, 2010) as well as parents (Gureje et al, 2011) increase the risk of transition from ideation to attempt. Specifically, alcohol-related aggression among patients with alcohol dependence was significantly associated with unplanned or ‘impulsive’ suicide attempts among ideators (Conner et al 2007). In our study, alcohol use disorders per se did not emerge as a transition risk factor and a history of alcohol dependence did not remain as a significant factor for future attempt in multivariate analysis. Whether the role of impulsivity is generalizable to other substance use disorders beyond alcohol dependence remains to be explored. A higher severity of suicidal ideation based on the Scale for Suicidal Ideation was significantly associated with both the transition to and the occurrence of future suicide attempts in single predictor models. This finding further adds to the body of evidence that suicidal ideation is indeed a precursor to future suicide attempt (Mendez-Bustos et al, 2003). Of note, our study also showed that the transition from ideation to attempt was commensurate with the level of severity of suicidal ideation although this did not remain significant in multivariate analysis. A review by Oquendo et al (2006) seemed to suggest that the predictive utility of suicidal ideation may be better understood when considered together with other suicidal risk and protective factors such as aggression, impulsivity and reasons for living. Further research in more adequately powered samples are needed to elucidate the predictive value and possible role of suicidal ideation as a mediating risk
factor rather than an independent predictor of subsequent suicidal plans or acts.
4.2 Social risk factors A low social class status based on occupation was significantly associated with the transition from suicidal ideation to attempt in both single and multivariate predictor models while baseline change in live events was non-significant. For future suicide attempt, the presence of major personal injury or illness was significant in univariate but not multivariate analysis. Change in other specific live events (marital separation and major mortgage or loan) rather than social class was significantly associated with baseline suicide attempt at index admission in the same study population (Chan et al, 2011). Social class may be viewed as a relatively stable socio-economic factor with more prominent effects on the progression along the continuum of suicidal behavior compared to other more transient social stresses such as life events. A Korean case-control study in the general population found that lower social class was significantly associated with completed suicides after controlling for gender, age, area of residence and marital status (. et al, 2006). Li et al.’s systematic review (2011) found that the population attributable risk (PAR) of suicide for low occupational status was comparable with PAR for mood and substance use disorders in males. Attempted suicide has also been linked to a lower social class or socioeconomic status, albeit mostly from population-based studies in highincome, Western nations (Burrows et al., 2010; Schmidtke et al., 1996). In terms of a clinical population, Cohen et al.’s (2009) study in geriatric depression showed that lower socioeconomic status not only predicted suicidal ideation but also a poorer response to treatment for depression. Socio-economic deprivation has been shown as a limiting factor
in accessing mental health resources and services in middle-income nations (Saxena et al, 2007) such as Malaysia. Therefore, a possible explanation for low social class as a risk factor for transitioning from suicidal ideation to attempt may lie in the disparities or inequities in access to mental healthcare that is experienced by those who are most vulnerable and disadvantaged socio-economically. Thus, a possible area of focus in future research is a more fine-grained analysis on health systems to elucidate the specific mechanisms of how low social class can tip the balance from suicidal ideation to attempt. This would potentially carry important implications on suicide preventive efforts such as improving access and provision of mental health services to socio-economically disadvantaged populations. Another highlighted area is the need to recognize and target specific clinical and social risk factors in preventing ‘suicide attempt naïve’ ideators from progressing to further more serious suicidal acts beyond the emphasis on past suicide attempters. Such a shift in focus on early intervention is strategic in terms of potentially breaking the vicious cycle of repeated attempts leading to further increased suicidal risk, chronic morbidity and mortality.
4.3 Limitations Results from the univariate analyses need to be interpreted with caution. This is because the probability of identifying at least one significant result due to chance would increase with a higher number of hypotheses being tested. Ideally, in such a situation whereby multiple comparisons are performed on a single set of data, the Bonferroni correction should be used to reduce the chances of false-positive results (type I errors) from
occurring. In this study, we also considered the issue of type II error (false-negative results) due to our small sample size. Therefore, we chose to set the significance level at the conventional value of p<0.05. A major limitation of this study is the small sample size. Although multivariate analysis was performed in an attempt to investigate the adjusted effects of predictors of future attempt and the transition from ideation to attempt among depressed inpatients, results from such an approach should be interpreted with much caution in view of the relatively low number of future suicide attempts (12/66). Another point that needs to be borne in mind is the risk of overestimating the effects measured due to the small sample size (reflected by the wide confidence intervals) (Park, 2013). Unstudied confounding risk factors for suicidal behaviour include personality disorders, social support and impulsivity. Generalizability of this study’s findings is somewhat limited to hospitalized patients who tend to have a higher severity of illness. Also, although participants were followed-up prospectively, the assessment of future suicide attempt was not done immediately following the attempt. Local validation of self-report questionnaires such as the Malay version of the SRRS and BDI in a similar population as the study participants would have been ideal.
4.4 Conclusions Our findings seem to suggest that previous psychiatric hospitalization is a significant shared prospective predictor of future suicide attempt and the transition from suicidal ideation to attempt in depressive disorders. Other shared risk factors from singlepredictor models include the severity of suicidal ideation and possibly substance use
disorders. Low socio-economic status may be a better predictor of the transition from ideation to attempt rather than change in specific life events that may be more associated with future attempt in general. Other risk factors from single predictor models that were unique to future suicide attempts and not the transition process include past suicide attempt, subjective rating of depression severity and compliance to medication. It would seem that suicidal ideation is a necessary but not sufficient condition in predicting future suicide attempt. Given the major limitation of sample size in this study, future research in larger samples is needed to confirm these findings and further elucidate the mechanisms underlying the interactions between predictors of the progression of suicidal behaviour.
Acknowledgements This study was funded by the National University of Malaysia Medical Centre Fundamental Research Grant (Project Code: FF-095-2007). The authors would like to thank Ms. Nur Ahlina Abdullah for her administrative assistance in the preparation of this manuscript.
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Table 1 Single predictor models for socio-demographic and clinical risk factors of future suicide attempt among depressed inpatients. Future Suicide Attempt
p
Socio-demographic factors
Yes (%)
No (%)
Age (years), mean (SD)
32.3 (7.3)
25.6 (13.9)
0.17a
Male gender
5 (41.7)
21 (38.9)
0.86
Malay ethnicity
5 (41.7)
19 (35.2)
Muslim religion
4 (33.3)
Unmarried
O.R.
95% CI Lower
Upper
1.12
0.32
4.00
0.50
1.84
0.31
10.92
19 (35.2)
0.31
0.21
0.01
4.12
5 (58.3)
17 (68.5)
0.50
1.56
0.43
5.61
Low educationi
2 (16.7)
7 (13.0)
0.74
1.34
0.24
7.45
Unemployed
6 (50.0)
29 (53.7)
0.82
1.16
0.33
4.06
1(8.3)
20 (37.0)
0.09
6.47
0.78
53.92
294 (139.1)
209 (219.2)
0.67b
4 (33.3)
5(9.3)
0.04
4.90
1.08
22.23
5 (41.7)
16 (29.6)
0.86
1.25
0.11
13.92
6 (50)
14 (25.9)
0.11
2.86
0.80
10.33
Melancholic symptoms
4 (33.3)
32 (59.3)
0.11
0.34
0.09
1.28
Previous psychiatric hospitalization
11(91.7)
24 (44.4)
0.02
13.75
1.66
114.13
Medication compliance
2 (18.2)
33 (61.1)
0.01
0.12
0.02
0.62
ECT treatment
2 (16.7)
7 (13)
0.60
1.60
0.28
9.11
9 (75)
21 (38.9)
0.03
4.71
1.14
19.437
Past suicide attempt at baseline
5 (41.7)
14 (25.9)
0.28
2.04
0.56
7.48
Current alcohol use disorder
5 (41.7)
10 (18.5)
0.09
3.14
0.83
11.97
Low social classii Baseline SRRS total score, median (SD) Major personal injury or illness Clinical factors Bipolar depression Psychotic symptoms
Past suicide attempt prior to baseline
Previous alcohol use disorder
6 (50)
12 (22)
0.04
7.00
1.14
42.97
Nicotine abuse or dependence
6 (50)
15 (27.8)
0.14
2.60
0.72
9.34
Any substance use disorderii
9 (75)
18 (33.3)
0.01
6.00
1.45
24.92
Anxiety disorder
3 (25)
7 (13)
0.30
2.24
0.49
10.33
Chronic medical condition
7 (58.3)
22 (40.7)
0.27
2.04
0.57
7.25
Family history of completed suicide
2 (16.7)
1 (1.9)
0.06
10.60
0.88
128.33
History of sexual abuse
4 (33.3)
9 (16.7)
0.20
2.50
0.62
10.11
Baseline BDI total score, mean (SD)
32 (20.9)
25.6 (13.9)
0.02c
Baseline SSI total score, median (SD)
13.5 (8.2)
6.5 (7.3)
<0.01d
Note: Univariate analysis using separate simple logistic regressions performed for categorical independent variables to predict future suicide attempt
i. below high school education ii. below middle class iii. alcohol, nicotine, amphetamine, opioid or benzodiazepine
a. b. c. d.
t=1.39, d.f.=64, independent t-test U=298, Z=-0.432, Mann Whitney test t = -2.370, d.f.=31.519, independent t-test U=136, Z = -3.132, Mann Whitney test
Table 2: Single predictor models for socio-demographic and clinical risk factors of the transition from suicidal ideation to future suicide attempt among depressed inpatients Future Suicide Attempt
p
Socio-demographic factors
Yes (%)
No (%)
Age (years), mean (SD)
40.25 (10.70)
44.32 (11.52)
0.17a
Male gender
5 (41.7)
15 (39.5)
0.89
Malay ethnicity
5 (41.7)
11 (68.8)
Muslim religion
4 (33.3)
11 (28.9)
O.R.
95% CI Lower
Upper
1.10
0.29
4.10
0.38
2.27
0.36
14.45
1.00
<0.01
<0.01
-1.80 x10283
Unmarried
5 (41.7)
11 (28.9)
0.41
1.75
0.46
6.73
Low educationi
2 (16.7)
2 (5.3)
0.23
3.60
0.45
28.86
6 (50)
15 (39.5)
0.52
1.53
0.42
5.66
11 (91.7)
21 (55.3)
<0.05
8.91
1.04
76.04
294 (139.122)
283 (227.643)
0.58b
5 (41.7)
11 (28.9)
0.81
1.36
0.11
16.58
6 (50)
11 (28.9)
0.19
2.46
0.65
9.29
Melancholic symptoms
4 (33.3)
24 (63.2)
0.08
3.43
0.87
13.48
Previous psychiatric hospitalization
11 (91.7)
16 (42.1)
0.01
15.13
1.77
129.33
Medication compliance
2 (18.2)
21 (55.3)
1.00
1.04
<0.01
-1.80
Unemployed Low social classii Baseline SRRS total score, median (SD) Clinical factors Bipolar depression Psychotic symptoms
x109 ECT treatment Past suicide attempt prior to baseline Past suicide attempt at baseline
x10283
2 (16.7)
5 (13.2)
0.76
1.32
0.22
7.87
9 (75)
19 (50)
0.14
3.00
0.70
12.83
5 (41.7)
14 (36.8)
0.76
1.22
0.33
4.60
Current alcohol use disorder
5 (41.7)
10 (26.3)
0.32
2.00
0.52
7.76
Previous alcohol use disorder
6 (50)
12 (31.6)
Nicotine abuse or dependence
6 (50)
13 (34.2)
0.33
1.92
0.52
7.16
Any substance use disorderiii
9 (75)
16 (42.1)
0.06
4.13
0.96
17.70
Anxiety disorder
3(25)
5 (13.2)
0.34
2.20
0.44
11.01
Chronic medical condition
7 (58.3)
16 (42.1)
0.33
1.93
0.52
7.178
Family history of completed suicide
2 (16.7)
1 (2.6)
0.12
7.40
0.61
90.15
History of sexual abuse
4 (33.3)
6 (15.8)
0.20
2.67
0.61
11.76
Baseline BDI total score, mean (SD)
32.33 (7.34)
28.84 (14.13)
0.27c
Baseline SSI total score, median (SD)
13.5 (7.83)
9.5 (7.32)
0.03d
Note: Univariate analysis using separate simple logistic regressions for categorical variables to predict future suicide attempt among suicidal ideators
i. below high school education ii. below middle class iii. alcohol, nicotine, amphetamine, opioid or benzodiazepine a. b. c. d.
t=1.08, d.f.= 48, independent t-test U=203.5, Z=-0.557, Mann Whitney test t = 1.18, d.f.=36.81, independent t-test U=131, Z = -2.209, Mann Whitney test
Table 3 Predictors of future suicide attempt based on multivariate logistic regression models B
S.E.
Wald,
p
O.R.
95% C.I. for
χ2 Future
attempt
A.O.R.
among
Unadjusted
Adjusted Lower
Upper
depressed inpatientsi Previous
psychiatric
2.93
1.18
6.23
0.01
13.75
18.76
1.88
187.71
Any substance use disordera
2.06
0.84
5.97
0.02
6
7.82
1.50
40.79
Major personal injury or illness
2.10
1.07
3.84
0.05
4.9
8.15
1.00
66.46
2.87
1.13
6.48
0.01
15.13
17.59
1.93
160.06
2.39
1.15
4.34
0.04
8.91
10.85
1.15
102.31
hospitalization
Transition from ideation to future attempt among suicidal ideatorsii Previous
psychiatric
hospitalization Low social classb
Note: A.O.R.=Adjusted odds ratio i. Nagelkerke R Square = 0. 46 ii. Nagelkerke R Square = 0. 43
a: alcohol, nicotine, amphetamine, opioid or benzodiazepine h: below middle class
Highlights • Hospitalization & ideation severity predicted ideation transition & future attempt • Social predictors differentiated between ideation transition & future attempt • Past attempt, depression severity & compliance uniquely predicted future attempt • Absence of prior attempt did not eliminate risk of future attempt
Figure 1: Summary of study respondents
Screened
population
=133
psychiatric inpatients with a clinical diagnosis of depressive disorder
17 ineligible patients •
15 couldn’t comprehend English/Malay
•
2 too ill to be interviewed
Eligible patients = 116 41 Non-responders •
11 refused consent
•
30 discharged before complete assessment
N1=75 participants at
9 participants lost to follow-
N2=66 participants within 1
Figure 2: Kaplan-Meier survival curve indicating number of days between hospital discharge and future suicide attempt
Are predictors of future suicide attempts and the transition from suicidal ideation to suicide attempts shared or distinct: A 12 - month prospective study among patients with depressive disorders. Lai Fong Chan, Shamsul Azhar Shah, Maniam Thambu www.elsevier.com/locate/psychres
PII: DOI: Reference:
S0165-1781(14)00752-5 http://dx.doi.org/10.1016/j.psychres.2014.08.055 PSY8523
To appear in:
Psychiatry Research
Received date: 12 May 2014 Revised date: 13 August 2014 Accepted date: 26 August 2014 Cite this article as: Lai Fong Chan, Shamsul Azhar Shah, Maniam Thambu, Are predictors of future suicide attempts and the transition from suicidal ideation to suicide attempts shared or distinct: A 12 - month prospective study among patients with depressive disorders., Psychiatry Research, http://dx.doi.org/10.1016/ j.psychres.2014.08.055 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Are predictors of future suicide attempts and the transition from suicidal ideation to suicide attempts shared or distinct: A 12 - month prospective study among patients with depressive disorders. Lai Fong Chana*, Shamsul Azhar Shahb, Maniam Thambua Dept. of Psychiatrya & Dept. of Community Medicineb, National University of Malaysia Medical Centre (UKMMC), Kuala Lumpur, Malaysia
*Corresponding author: Dr. Lai Fong Chan Associate Professor & Consultant Psychiatrist Department of Psychiatry Universiti Kebangsaan Malaysia Medical Centre (UKMMC) Jalan Yaacob Latif Bandar Tun Razak Cheras, 56000 Kuala Lumpur, Malaysia Tel no: +60391456143 Fax no: +60391456681 Email address: [email protected]
ABSTRACT Our study aimed to examine the interplay between clinical and social predictors of future suicide attempt and the transition from suicidal ideation to suicide attempt in depressive disorders. Sixty-six Malaysian inpatients with a depressive disorder were assessed at index admission and within 1 year for suicide attempt, suicidal ideation, depression severity, life event changes, treatment history and relevant clinical and sociodemographic factors.
One-fifth of suicidal ideators transitioned to a future suicide
attempt. All future attempters (12/66) had prior ideation and 83% of attempters had a prior attempt. The highest risk for transitioning from ideation to attempt was 5 months post-discharge. Single predictor models showed that previous psychiatric hospitalization and ideation severity were shared predictors of future attempt and ideation to attempt transition. Substance use disorders (especially alcohol) predicted future attempt and approached significance for the transition process. Low socio-economic status predicted the transition process while major personal injury/illness predicted future suicide attempt. Past suicide attempt, subjective depression severity and medication compliance predicted only future suicide attempt. The absence of prior suicide attempt did not eliminate the risk of future attempt. Given the limited sample, future larger studies on mechanisms underlying the interactions of such predictors are needed.
Key words: future suicide attempt, transition ideation to attempt, clinical & social predictors
1. Introduction Suicide is a leading cause of death worldwide (Mathers et al., 2006). Morbidity due to self-harm including suicide attempts has increased dramatically by 136% within the past decade (Institute for Health Metrics and Evaluation, 2013). One of the key processes in the prevention of suicidal behavior involves the accurate identification of those who are at highest risk of suicidal acts (attempted or completed suicide). Such highrisk populations have been identified among inpatients with depressive disorders (Bostwick, and Pankratz, 2003). Prospective studies in patients with unipolar and bipolar depression have demonstrated the following predictive risk factors for future suicidal acts: past suicide attempts, duration spent in major depressive episodes, lack of a partner (Sokero et al., 2005); severity of subjective rating of depression, cigarette smoking (Oquendo et al., 2004), alcohol use disorders (Oquendo et al., 2006); younger onset of illness, bipolar diagnosis and psychiatric hospitalizations (Tondo et al., 2007). The role of suicidal ideation as a risk factor for more serious suicidal acts has been somewhat mixed in the literature. Busch et al.’s (2003) retrospective chart review found that only 39% of patients, mostly depressed, who eventually committed suicide had endorsed suicidal ideation a week before committing suicide (8). A more recent review by Mendez-Bustos et al. (2003) found that greater suicidal ideation was significantly associated with re-attempted suicide. The evaluation of suicidal ideation is crucial in suicidal risk assessment as it can be viewed as the gateway to more serious suicidal acts. Large et al. (2013) highlighted the challenge of predicting who among those with suicidal ideation will eventually complete suicide, partly due to the non-specificity of wellestablished risk factors of suicidal behavior. Although there is a growing body of
literature that has examined the differences between suicidal ideators and attempters cross-sectionally (Klonsky et al., 2014), an important knowledge gap still exists with regards to understanding the critical transition from suicidal ideation to attempts. Retrospective, population-based studies have shown that prior suicidal behaviours i.e. previous plans, earlier onset of ideation onset (ten Have et al., 2013) and psychiatric disorders such as substance, bipolar, conduct and post-traumatic stress disorders predicted the transition from ideation to plans and attempts (Nock et al., 2010). Yang et al’s (2014) prospective study among Chinese medical students demonstrated the following transition risk factors: history of suicidal behavior in first-degree relatives, severe anxiety symptoms, impulsivity, physical abuse and parental divorce. The conundrum that most clinicians face is to identify which suicidal ideator will eventually attempt suicide. Such a decision carries important implications on the intensiveness of management and utilization of resources in mental health services i.e. outpatient versus inpatient treatment. May et al.’s (2012) prospective study among 49 patients with depressive disorders demonstrated that cluster B personality disorders independently predicted future suicide attempts from ideators after accounting for the most robust predictor from existing literature, a history of past attempt. Apart from that study, the evidence-base for risk assessment of depressed patients progressing from suicidal ideation to attempts is still scarce, more so among non-Western populations. Another crucial clinical question that needs to be addressed is whether predictors of future attempts are distinct or overlap with predictors of the transition from ideation to attempts.
Aims of the study Our aim in this study was to examine the interplay between clinical and social predictors of (i) future suicide attempt and (ii) the transition from suicidal ideation to suicide attempt among patients with depressive disorders in a Malaysian sample.
2. Methods
2.1 Participants and procedures In this paper, we report the prospective data from a 1-year longitudinal naturalistic cohort of patients admitted to the psychiatric wards of the National University of Malaysia Medical Centre (UKMMC), a tertiary-level, teaching hospital in Kuala Lumpur, the capital city situated in Peninsular Malaysia. Malaysia is an upper middle income South East Asian nation with an ethnic composition (Peninsular Malaysia) of Malays (63.1%), Chinese (24.6%), Indians (7.3%), indigenous groups (4.3%) and others (0.7%) (Department of Statistics, Malaysia, 2011). This study was approved by the Research and Ethics Committee of the National University of Malaysia Medical Centre and registered with the National Medical Research Register of Malaysia (NMRR ID No: NMRR-12-1082-14456). A hundred and thirty three consecutive psychiatric inpatients were screened for study recruitment from May 2007 to October 2008. One hundred and sixteen patients met eligibility criteria: 18 to 76 years of age; diagnosed with a depressive disorder according to DSM-IV-TR; able to comprehend English or Malay (the national language of Malaysia) and were not too ill or psychotic to undergo study assessments. Seventy-five patients gave written informed consent and completed a baseline evaluation within 72
hours of admission. A diagnosis of depressive disorder was confirmed with the Structured Clinical Interview for DSM-IV Axis I Disorders, Clinician Version (SCID I/CV), (First et al. 1997). A comprehensive clinical interview during SCID–I/CV administration was done together with other interviewer-rated and self-report questionnaires detailed below. Study participants were interviewed in a room where privacy and confidentiality were assured. The interviews were conducted by a masterslevel psychiatric resident (LFC) trained and supervised by a senior consultant psychiatrist (MT) during the course of the study in the usage of study instruments. Data collected included socio-demographic and clinical factors such as the presence or absence of suicidal ideation, suicide attempt (current and previous), severity of suicidal ideation and depression, previous history of psychiatric hospitalization, psychotic or melancholic features, co-morbid substance use and medical conditions, treatment history (medication compliance, ECT), history of sexual abuse, family history of attempted or completed suicide and recent life event changes. At baseline, participants were mostly female (56%), married (66.7%) and below middle social class (62.7%). Participants’ age ranged from 18-76 years with a mean of 43.8 years (s.d.=12.1). Ethnic composition was consistent with the hospital service utilization demographics of an urban Malaysian population but somewhat different from the general population: Chinese (40%) of whom 46.6% were Christians and 53.3% were Buddhists-Taoists; Malays (37.3%) who were exclusively Muslim, and Indians (22.7%) who were predominantly Hindus (82.4%). In terms of treatment, 32% of cases were on at least 1 mood-stabiliser and 67% were on at least 1 antidepressant (SSRI/SNRI) while 13.6% received ECT treatment. Further details on clinical and socio-demographic characteristics have been reported elsewhere (Chan et
al. 2011; Chan et al., 2012). Study participants were assessed at baseline and followed-up within 12 months from baseline. Follow-up data was available for 66 participants, including 89% of baseline suicidal ideators (50/56) (Figure 1). All interviews were conducted in person except for 6 patients over the phone. Socio-demographic and clinical characteristics of the 9 patients that were lost to follow-up (12 % attrition rate) did not differ significantly from the 66 participants assessed longitudinally except for having a lower baseline median SSI score by 5 points (p<0.05).
2.2 Measures 2.2.1 Suicidal behaviour Suicidal behavior was assessed from the clinical interview and psychiatric records. A suicide attempt was coded as having occurred in the past prior to baseline, at baseline as part of the SCID and in future after baseline during the follow-up assessment in the event of any act of self-harm with inferred or explicit intent to (4, 5, 18). Suicidal ideation was determined as present at baseline and in the future after baseline if the patient had the thought or intention of attempting suicide from clinical interview. The severity of suicidal ideation was evaluated with the Scale for Suicidal ideation (SSI), an interviewer-administered rating scale with adequate convergent and construct and validity as well as Cronbach coefficient alpha ranging from 0.84 to 0.89 among psychiatric inpatients (Beck et al. 1979).
2.2.2 Diagnostic, clinical and psychosocial variables The SCID – I/CV was used for Axis I depressive disorder diagnoses including comorbid anxiety disorders and substance use disorders as well as assessment of the following clinical variables: psychotic or melancholic features, previous history of psychiatric hospitalization, medication and ECT treatment, history of sexual abuse and family history of attempted or completed suicide. The severity of depression in the past one week of assessment was evaluated at baseline and follow-up with the national language (Malay) version of the 21-item Beck Depression Inventory (BDI) (Cronbach’s alpha=0.965) (Chan et al. 2011). The Malay version of the Social Readjustment Rating Scale (SRRS) assessed patients’ self-report on the magnitude of life event changes within the past 12 months of assessment at baseline and follow-up. The original English SRRS demonstrated good concordance (Spearman's rho: 0.97 to 0.91) between Malaysian and American samples in terms of the order of magnitude to changes in life events (20). This Malay version of the SRRS was modified with permission from a Malay version translated by Othman (1986), including the addition of 20 questions that Othman had excluded from the original SRRS. This author and Othman both used the back-translation technique. Assessment of compliance was based on participants’ self-report of not missing more than 30% of prescribed medication (Scott, 2000) within the period of baseline and follow-up assessment. Socio-demographic data included age, gender, marital status, ethnicity, religion, employment status, educational level and social class based on occupational status according to the National Readership Survey (NRS) social grade, United Kingdom.
2.3 Statistical analysis Data was analysed using the Statistical Package for the Social Sciences (SPSS) software, version 21. Univariate analysis was performed with simple logistic regression for categorical independent variables. Two dependent variables were analysed as dichotomous (yes/no) variables: (i) future suicide attempt in the total sample population (with and without baseline suicidal ideation) and (ii) future suicide attempt among baseline suicidal ideators (transition from ideation to attempt). The following variables were analysed as dichotomous independent variables: gender, marital status, social class (middle class and above/below middle class), education (high school and above/lower than high school), employment, suicidal ideation, past and baseline suicide attempt, psychotic or melancholic features, previous history of psychiatric hospitalization, medication and ECT treatment, medication compliance, chronic medical condition, history of sexual abuse, family history of attempted or completed suicide and each of the 43 items of change in live events in the SRSS (present/absent). Other categorical independent variables included: ethnicity, religion, and diagnoses of depressive, anxiety and substance disorders. The following baseline independent variables were analysed as continuous scores: age (independent t-test), severity of depression (BDI) (independent ttest), severity of suicidal ideation (SSI) (Mann Whitney test), magnitude of life event changes (SRSS) (Mann Whitney test). Significant independent variables from univariate analysis (p<0.05) were entered into multivariate logistic regression models using the forward conditional method to determine the independent predictive risk factors for (i) future suicide attempt in the total sample population (with and without baseline suicidal ideation) and (ii) future suicide attempt among baseline suicidal ideators (transition from
ideation to attempt). Kaplan-Meier survival analysis was used to estimate the highest risk of future suicide attempt. 3. Results
3.1 Description of suicidal behaviour Twelve out of 66 patients (18.2%) had made at least one suicide attempt during the 1-year follow-up period, all of which had baseline suicidal ideation. Thirty percent (9/30) of patients with a past suicide attempt prior to baseline, and 28.8% (5/19) with an index suicide attempt at baseline reattempted suicide within a year. Twenty four percent of baseline suicidal ideators (12/50) subsequently attempted suicide. Seventeen percent (2/12) of future suicide attempters did not have any history of suicide attempt prior to or at baseline.
3.2 Period of highest risk of suicide attempt From the Kaplan-Meier survival analysis, 9 out of the 12 future suicide attempts (75%) occurred within 149 days (5 months) post-discharge, after which the rate dropped significantly (Figure 2). Therefore, the period of highest risk of a subsequent suicide attempt is estimated to be within 5 months after hospital discharge. Survival analysis for the transition from ideation to attempt is similar because all future attempts were preceded by baseline suicidal ideation.
3.3 Risk factors for future suicide attempt Univariate analysis from simple logistic regression found the following factors to be significantly associated with future suicide attempt: previous psychiatric hospitalization (p=0.02, OR=13.75, 95%CI=1.66-114.13), past suicide attempt prior to baseline assessment (p=0.03, OR=4.71, 95%CI=1.14-19.44), history of alcohol dependence (p=0.04, OR=7, 95% CI=1.14-42.97), any type of substance use disorder i.e. alcohol, nicotine, amphetamine, opioid or benzodiazepine (p=0.01, OR=6, 95% CI=1.45-24.92), severity of suicidal ideation at baseline (higher baseline SSI total score) (p<0.01, U=136, z=-3.132), severity of subjective ratings of depression at baseline (higher baseline BDI total score) (p=0.02, t = -2.370, d.f. = 31.52) and the presence of major personal injury or illness from baseline SRRS (p=0.03, OR=4.9, 95% CI=1.08-22.23). Compliance to medication was found to be a protective factor against future suicide attempt (p=0.01; OR=0.12; 95%CI=0.02-0.62) (Table 1). A multivariate logistic regression model, which included factors from univariate analysis with p<0.05 showed that previous psychiatric hospitalization was the strongest predictor of a future suicide attempt (B=2.93, p=0.01, OR=18.76, 95%CI=1.88-187.71) followed by any type of substance use disorder (B=2.06, p=0.02, OR=7.82, 95% CI=1.50-40.79) (Table 3). The presence of major personal injury or illness from baseline SRRS approached a trend towards significance (B=2.10, p=0.05, OR=8.15, 95%CI=1.0 - 66.46). The sensitivity, specificity and area under the ROC curve (AUC) for this multivariate model are as follows: sensitivity=75%, specificity=83.3% and AUC=0.87.
3.4 Risk factors for transition of suicidal ideation to attempt Univariate analysis from binary logistic regression showed the following factors to be significantly associated with future suicide attempt among baseline suicide ideators: low social class (below middle class) (p=0.046, OR=8.91, 95%CI=1.04-76.04), previous psychiatric hospitalization (p=0.01, OR=15.13, 95%CI=1.77-129.33), and severity of suicidal ideation at baseline (higher baseline SSI total median scores) (p=0.03; OR=1.10; 95%CI=1.01-1.20). The presence of any type of substance use disorder (alcohol, nicotine, amphetamine, opioid or benzodiazepine) showed a trend towards significance (p=0.06; OR=4.13; 95% CI=0.96-17.70) (Table 2). No individual items of change in life events from the SRRS were significant factors. A multivariate logistic regression model which included factors from univariate analysis with p<0.05 showed that previous psychiatric hospitalization was the strongest predictor of the transition from baseline suicidal ideation to future suicide attempt (B=2.87, p=0.005, OR=57.702, (95%C.I.=3.3171003.706) followed by low social class (B=2.39, p=0.04, OR=10.85, (95%CI=1.15102.31) (Table 3). The sensitivity, specificity and area under the ROC curve (AUC) for this multivariate model are as follows: sensitivity=83.3%, specificity=78.9% and AUC=0.84.
4. Discussion We found that 24% of suicidal ideators progressed to attempted suicide among inpatients with depressive disorders. This finding was comparable to May et al.’s (2012) figure of 26.5%. Our finding that the rate of suicide attempts, including the transition from ideation to attempt was highest within the 5-month post-discharge period concurs
with Oquendo et al. (2004) which showed that the period of highest risk for future suicidal acts was within the first year after discharge.
4.1 Clinical risk factors. Previous psychiatric hospitalization has been established as a common risk factor for attempted suicide (Beautrais, 2001), especially in mood disorders (Botswick and Pankratz, 2000; Angst et al, 2002). We replicated this finding in terms of future suicide attempts and the transition from ideation to attempt in our univariate analysis. In fact, previous psychiatric hospitalization emerged as the strongest predictor that differentiated between suicidal ideators who progressed to a future attempt from those who did not attempt, as well as for future attempts in general. Patients’ subjective ratings of baseline depression severity during index admission were significantly associated with a future suicide attempt from univariate but not multivariate analysis. However, depression severity was not shown to be significantly associated with the transition from ideation to attempt even in the univariate analysis. A history of previous psychiatric hospitalization may be more representative of objective severity and functional impairment with a higher impact on the progression from ideation to attempt over a longitudinal course of illness compared to an acute subjective rating of depression. Also, the decision to hospitalize a depressed patient is often based on the clinical assessment of the level of suicidal risk in each individual case (Botswick and Pankratz, 2000). As expected, past suicide attempt prior to baseline was a predictor of a future attempt from our univariate analysis. However, this was not shown to be an independent predictor of future suicide attempt. This is a departure from the well-replicated finding
that past attempt is one of the most robust predictors of future attempt. On top of that, past suicide attempt did not predict the transition from ideation to attempt even in the univariate analysis. This is possibly because of a type II error due to the limitation of our sample size. Nevertheless, the absence of past suicide attempt does not negate the risk of a future suicide attempt as a substantial minority (16.7%) of future suicide attempters did not have any prior attempts. Compliance to medication (mainly antidepressants e.g. SSRIs/SNRIs) was protective against future suicide attempts in the univariate analysis. This is an important finding as there is a current lack of direct evidence that supports the role of antidepressant adherence in reducing rather than increasing future suicidal acts (Woldu et al, 2011). However, this association failed to remain significant in multivariate analysis for future attempt and was not significantly associated with the transition process in the univariate analysis either, highlighting the need for further studies in this area with larger sample size. Our study showed that any type of substance use disorder was significantly associated with future attempt. The association with the transition from ideation to attempt also approached significance in single predictor models. Specifically, a history of alcohol dependence predicted future attempts in univariate analysis. This concurs with previous longitudinal studies that has highlighted the role of comorbid substance disorders as a significant risk factor for suicidal behaviour in mood disorders, both in population-based (Bolton et al, 2011) and clinical samples, especially alcohol (Maser et al, 2002).
Several lines of evidence from previous research point towards impulsivity as a possible mechanism underlying the role of substance disorders in leading to future suicide attempts, in particular, the pathway of transitioning from ideation to attempt. Population studies have demonstrated that impulse-control disorders in probands (Nock et al, 2010) as well as parents (Gureje et al, 2011) increase the risk of transition from ideation to attempt. Specifically, alcohol-related aggression among patients with alcohol dependence was significantly associated with unplanned or ‘impulsive’ suicide attempts among ideators (Conner et al 2007). In our study, alcohol use disorders per se did not emerge as a transition risk factor and a history of alcohol dependence did not remain as a significant factor for future attempt in multivariate analysis. Whether the role of impulsivity is generalizable to other substance use disorders beyond alcohol dependence remains to be explored. A higher severity of suicidal ideation based on the Scale for Suicidal Ideation was significantly associated with both the transition to and the occurrence of future suicide attempts in single predictor models. This finding further adds to the body of evidence that suicidal ideation is indeed a precursor to future suicide attempt (Mendez-Bustos et al, 2003). Of note, our study also showed that the transition from ideation to attempt was commensurate with the level of severity of suicidal ideation although this did not remain significant in multivariate analysis. A review by Oquendo et al (2006) seemed to suggest that the predictive utility of suicidal ideation may be better understood when considered together with other suicidal risk and protective factors such as aggression, impulsivity and reasons for living. Further research in more adequately powered samples are needed to elucidate the predictive value and possible role of suicidal ideation as a mediating risk
factor rather than an independent predictor of subsequent suicidal plans or acts.
4.2 Social risk factors A low social class status based on occupation was significantly associated with the transition from suicidal ideation to attempt in both single and multivariate predictor models while baseline change in live events was non-significant. For future suicide attempt, the presence of major personal injury or illness was significant in univariate but not multivariate analysis. Change in other specific live events (marital separation and major mortgage or loan) rather than social class was significantly associated with baseline suicide attempt at index admission in the same study population (Chan et al, 2011). Social class may be viewed as a relatively stable socio-economic factor with more prominent effects on the progression along the continuum of suicidal behavior compared to other more transient social stresses such as life events. A Korean case-control study in the general population found that lower social class was significantly associated with completed suicides after controlling for gender, age, area of residence and marital status (. et al, 2006). Li et al.’s systematic review (2011) found that the population attributable risk (PAR) of suicide for low occupational status was comparable with PAR for mood and substance use disorders in males. Attempted suicide has also been linked to a lower social class or socioeconomic status, albeit mostly from population-based studies in highincome, Western nations (Burrows et al., 2010; Schmidtke et al., 1996). In terms of a clinical population, Cohen et al.’s (2009) study in geriatric depression showed that lower socioeconomic status not only predicted suicidal ideation but also a poorer response to treatment for depression. Socio-economic deprivation has been shown as a limiting factor
in accessing mental health resources and services in middle-income nations (Saxena et al, 2007) such as Malaysia. Therefore, a possible explanation for low social class as a risk factor for transitioning from suicidal ideation to attempt may lie in the disparities or inequities in access to mental healthcare that is experienced by those who are most vulnerable and disadvantaged socio-economically. Thus, a possible area of focus in future research is a more fine-grained analysis on health systems to elucidate the specific mechanisms of how low social class can tip the balance from suicidal ideation to attempt. This would potentially carry important implications on suicide preventive efforts such as improving access and provision of mental health services to socio-economically disadvantaged populations. Another highlighted area is the need to recognize and target specific clinical and social risk factors in preventing ‘suicide attempt naïve’ ideators from progressing to further more serious suicidal acts beyond the emphasis on past suicide attempters. Such a shift in focus on early intervention is strategic in terms of potentially breaking the vicious cycle of repeated attempts leading to further increased suicidal risk, chronic morbidity and mortality.
4.3 Limitations Results from the univariate analyses need to be interpreted with caution. This is because the probability of identifying at least one significant result due to chance would increase with a higher number of hypotheses being tested. Ideally, in such a situation whereby multiple comparisons are performed on a single set of data, the Bonferroni correction should be used to reduce the chances of false-positive results (type I errors) from
occurring. In this study, we also considered the issue of type II error (false-negative results) due to our small sample size. Therefore, we chose to set the significance level at the conventional value of p<0.05. A major limitation of this study is the small sample size. Although multivariate analysis was performed in an attempt to investigate the adjusted effects of predictors of future attempt and the transition from ideation to attempt among depressed inpatients, results from such an approach should be interpreted with much caution in view of the relatively low number of future suicide attempts (12/66). Another point that needs to be borne in mind is the risk of overestimating the effects measured due to the small sample size (reflected by the wide confidence intervals) (Park, 2013). Unstudied confounding risk factors for suicidal behaviour include personality disorders, social support and impulsivity. Generalizability of this study’s findings is somewhat limited to hospitalized patients who tend to have a higher severity of illness. Also, although participants were followed-up prospectively, the assessment of future suicide attempt was not done immediately following the attempt. Local validation of self-report questionnaires such as the Malay version of the SRRS and BDI in a similar population as the study participants would have been ideal.
4.4 Conclusions Our findings seem to suggest that previous psychiatric hospitalization is a significant shared prospective predictor of future suicide attempt and the transition from suicidal ideation to attempt in depressive disorders. Other shared risk factors from singlepredictor models include the severity of suicidal ideation and possibly substance use
disorders. Low socio-economic status may be a better predictor of the transition from ideation to attempt rather than change in specific life events that may be more associated with future attempt in general. Other risk factors from single predictor models that were unique to future suicide attempts and not the transition process include past suicide attempt, subjective rating of depression severity and compliance to medication. It would seem that suicidal ideation is a necessary but not sufficient condition in predicting future suicide attempt. Given the major limitation of sample size in this study, future research in larger samples is needed to confirm these findings and further elucidate the mechanisms underlying the interactions between predictors of the progression of suicidal behaviour.
Acknowledgements This study was funded by the National University of Malaysia Medical Centre Fundamental Research Grant (Project Code: FF-095-2007). The authors would like to thank Ms. Nur Ahlina Abdullah for her administrative assistance in the preparation of this manuscript.
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Table 1 Single predictor models for socio-demographic and clinical risk factors of future suicide attempt among depressed inpatients. Future Suicide Attempt
p
Socio-demographic factors
Yes (%)
No (%)
Age (years), mean (SD)
32.3 (7.3)
25.6 (13.9)
0.17a
Male gender
5 (41.7)
21 (38.9)
0.86
Malay ethnicity
5 (41.7)
19 (35.2)
Muslim religion
4 (33.3)
Unmarried
O.R.
95% CI Lower
Upper
1.12
0.32
4.00
0.50
1.84
0.31
10.92
19 (35.2)
0.31
0.21
0.01
4.12
5 (58.3)
17 (68.5)
0.50
1.56
0.43
5.61
Low educationi
2 (16.7)
7 (13.0)
0.74
1.34
0.24
7.45
Unemployed
6 (50.0)
29 (53.7)
0.82
1.16
0.33
4.06
1(8.3)
20 (37.0)
0.09
6.47
0.78
53.92
294 (139.1)
209 (219.2)
0.67b
4 (33.3)
5(9.3)
0.04
4.90
1.08
22.23
5 (41.7)
16 (29.6)
0.86
1.25
0.11
13.92
6 (50)
14 (25.9)
0.11
2.86
0.80
10.33
Melancholic symptoms
4 (33.3)
32 (59.3)
0.11
0.34
0.09
1.28
Previous psychiatric hospitalization
11(91.7)
24 (44.4)
0.02
13.75
1.66
114.13
Medication compliance
2 (18.2)
33 (61.1)
0.01
0.12
0.02
0.62
ECT treatment
2 (16.7)
7 (13)
0.60
1.60
0.28
9.11
9 (75)
21 (38.9)
0.03
4.71
1.14
19.437
Past suicide attempt at baseline
5 (41.7)
14 (25.9)
0.28
2.04
0.56
7.48
Current alcohol use disorder
5 (41.7)
10 (18.5)
0.09
3.14
0.83
11.97
Low social classii Baseline SRRS total score, median (SD) Major personal injury or illness Clinical factors Bipolar depression Psychotic symptoms
Past suicide attempt prior to baseline
Previous alcohol use disorder
6 (50)
12 (22)
0.04
7.00
1.14
42.97
Nicotine abuse or dependence
6 (50)
15 (27.8)
0.14
2.60
0.72
9.34
Any substance use disorderii
9 (75)
18 (33.3)
0.01
6.00
1.45
24.92
Anxiety disorder
3 (25)
7 (13)
0.30
2.24
0.49
10.33
Chronic medical condition
7 (58.3)
22 (40.7)
0.27
2.04
0.57
7.25
Family history of completed suicide
2 (16.7)
1 (1.9)
0.06
10.60
0.88
128.33
History of sexual abuse
4 (33.3)
9 (16.7)
0.20
2.50
0.62
10.11
Baseline BDI total score, mean (SD)
32 (20.9)
25.6 (13.9)
0.02c
Baseline SSI total score, median (SD)
13.5 (8.2)
6.5 (7.3)
<0.01d
Note: Univariate analysis using separate simple logistic regressions performed for categorical independent variables to predict future suicide attempt
i. below high school education ii. below middle class iii. alcohol, nicotine, amphetamine, opioid or benzodiazepine
a. b. c. d.
t=1.39, d.f.=64, independent t-test U=298, Z=-0.432, Mann Whitney test t = -2.370, d.f.=31.519, independent t-test U=136, Z = -3.132, Mann Whitney test
Table 2: Single predictor models for socio-demographic and clinical risk factors of the transition from suicidal ideation to future suicide attempt among depressed inpatients Future Suicide Attempt
p
Socio-demographic factors
Yes (%)
No (%)
Age (years), mean (SD)
40.25 (10.70)
44.32 (11.52)
0.17a
Male gender
5 (41.7)
15 (39.5)
0.89
Malay ethnicity
5 (41.7)
11 (68.8)
Muslim religion
4 (33.3)
11 (28.9)
O.R.
95% CI Lower
Upper
1.10
0.29
4.10
0.38
2.27
0.36
14.45
1.00
<0.01
<0.01
-1.80 x10283
Unmarried
5 (41.7)
11 (28.9)
0.41
1.75
0.46
6.73
Low educationi
2 (16.7)
2 (5.3)
0.23
3.60
0.45
28.86
6 (50)
15 (39.5)
0.52
1.53
0.42
5.66
11 (91.7)
21 (55.3)
<0.05
8.91
1.04
76.04
294 (139.122)
283 (227.643)
0.58b
5 (41.7)
11 (28.9)
0.81
1.36
0.11
16.58
6 (50)
11 (28.9)
0.19
2.46
0.65
9.29
Melancholic symptoms
4 (33.3)
24 (63.2)
0.08
3.43
0.87
13.48
Previous psychiatric hospitalization
11 (91.7)
16 (42.1)
0.01
15.13
1.77
129.33
Medication compliance
2 (18.2)
21 (55.3)
1.00
1.04
<0.01
-1.80
Unemployed Low social classii Baseline SRRS total score, median (SD) Clinical factors Bipolar depression Psychotic symptoms
x109 ECT treatment Past suicide attempt prior to baseline Past suicide attempt at baseline
x10283
2 (16.7)
5 (13.2)
0.76
1.32
0.22
7.87
9 (75)
19 (50)
0.14
3.00
0.70
12.83
5 (41.7)
14 (36.8)
0.76
1.22
0.33
4.60
Current alcohol use disorder
5 (41.7)
10 (26.3)
0.32
2.00
0.52
7.76
Previous alcohol use disorder
6 (50)
12 (31.6)
Nicotine abuse or dependence
6 (50)
13 (34.2)
0.33
1.92
0.52
7.16
Any substance use disorderiii
9 (75)
16 (42.1)
0.06
4.13
0.96
17.70
Anxiety disorder
3(25)
5 (13.2)
0.34
2.20
0.44
11.01
Chronic medical condition
7 (58.3)
16 (42.1)
0.33
1.93
0.52
7.178
Family history of completed suicide
2 (16.7)
1 (2.6)
0.12
7.40
0.61
90.15
History of sexual abuse
4 (33.3)
6 (15.8)
0.20
2.67
0.61
11.76
Baseline BDI total score, mean (SD)
32.33 (7.34)
28.84 (14.13)
0.27c
Baseline SSI total score, median (SD)
13.5 (7.83)
9.5 (7.32)
0.03d
Note: Univariate analysis using separate simple logistic regressions for categorical variables to predict future suicide attempt among suicidal ideators
i. below high school education ii. below middle class iii. alcohol, nicotine, amphetamine, opioid or benzodiazepine a. b. c. d.
t=1.08, d.f.= 48, independent t-test U=203.5, Z=-0.557, Mann Whitney test t = 1.18, d.f.=36.81, independent t-test U=131, Z = -2.209, Mann Whitney test
Table 3 Predictors of future suicide attempt based on multivariate logistic regression models B
S.E.
Wald,
p
O.R.
95% C.I. for
χ2 Future
attempt
A.O.R.
among
Unadjusted
Adjusted Lower
Upper
depressed inpatientsi Previous
psychiatric
2.93
1.18
6.23
0.01
13.75
18.76
1.88
187.71
Any substance use disordera
2.06
0.84
5.97
0.02
6
7.82
1.50
40.79
Major personal injury or illness
2.10
1.07
3.84
0.05
4.9
8.15
1.00
66.46
2.87
1.13
6.48
0.01
15.13
17.59
1.93
160.06
2.39
1.15
4.34
0.04
8.91
10.85
1.15
102.31
hospitalization
Transition from ideation to future attempt among suicidal ideatorsii Previous
psychiatric
hospitalization Low social classb
Note: A.O.R.=Adjusted odds ratio i. Nagelkerke R Square = 0. 46 ii. Nagelkerke R Square = 0. 43
a: alcohol, nicotine, amphetamine, opioid or benzodiazepine h: below middle class
Highlights • Hospitalization & ideation severity predicted ideation transition & future attempt • Social predictors differentiated between ideation transition & future attempt • Past attempt, depression severity & compliance uniquely predicted future attempt • Absence of prior attempt did not eliminate risk of future attempt
Figure 1: Summary of study respondents
Screened
population
=133
psychiatric inpatients with a clinical diagnosis of depressive disorder
17 ineligible patients •
15 couldn’t comprehend English/Malay
•
2 too ill to be interviewed
Eligible patients = 116 41 Non-responders •
11 refused consent
•
30 discharged before complete assessment
N1=75 participants at
9 participants lost to follow-
N2=66 participants within 1
Figure 2: Kaplan-Meier survival curve indicating number of days between hospital discharge and future suicide attempt