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The association of suicide attempts and comorbid depression and substance abuse in psychiatric consultation patients
The Association of Suicide Attempts and Comorbid Depression and Substance Abuse in Psychiatric Consultation Patients Dirk M. Dhossche, M.D., Aysha M. Meloukheia, M.D., and Subhajit Chakravorty, M.D. Abstract: Substance abuse has been associated with attempted suicide and suicide. Few studies have examined the prevalence and associations of combined depression and substance abuse in suicide attempters. A chart review study of 1136 adult general hospital patients referred for psychiatric consultation between 1995 and 1998 was conducted to assess this further. Among 371 cases with self-harm, 311 (84%) attempted suicide. Suicide attempters were younger and diagnosed more often with comorbid substance abuse than patients without self-harm. Depressive disorders were found in 59% and substance abuse disorders in 46%. Comorbid depression and substance abuse was the most frequent category in suicide attempters, i.e., in 37%. Self-reported suicide intent was associated with increasing age, male gender, and comorbid depression and substance abuse. The suicide rate in suicide attempters was 322 per 100,000 patient-years, and 131 per 100,000 in consultation patients without self-harm. It is concluded that comorbid depression and substance abuse is associated with attempted suicide in psychiatric consultation patients. Suicide attempters should be thoroughly assessed for substance abuse. The increased suicide rate in psychiatric consultation patients with and without suicide attempts warrants further research. © 2000 Elsevier Science Inc.
Introduction Psychiatric consultation is often requested for suicide attempters who are admitted to the general hospital. Some studies have suggested that it may be very difficult to prevent future attempts or suiDepartment of Psychiatry, University of South Alabama College of Medicine, Mobile, Alabama (D.M.D., A.M.M.), Department of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic, Pittsburgh, Pennsylvania (S.C.). Address reprint requests to: D.M. Dhossche, M.D., Reinpad Straat 98 Bus 12, 3600 Genk, Belgium.
General Hospital Psychiatry 22, 281–288, 2000 © 2000 Elsevier Science Inc. All rights reserved. 655 Avenue of the Americas, New York, NY 10010
cide [1], although psychiatric intervention is considered beneficial. Further study of this population may uncover new risk factors amenable to treatment or new markers for risk [2]. Alternatively, prevention of suicide may require broader changes in mental health care not limited to high-risk populations [3]. Suicide attempters are thought to be diagnostically heterogeneous with complicated psychosocial and psychiatric conditions as suggested by high comorbidity of psychiatric disorders, i.e., the co-occurrence of several disorders in one person [4,5]. There are several leads suggesting that substance abuse increases suicide risk [6 – 8]. Further examination of the role of comorbid substance abuse and other psychiatric disorders, especially depressive disorders, in suicidal behavior is warranted. Studies have supported the dimensional nature of intent to die in suicide attempters [9,10]. Clinicians routinely ask whether the patient with deliberate self-harm intended to die. This piece of information is often essential for treatment planning. Further studies on self-reported suicide intent are useful. In this study, findings in a new sample of suicide attempters admitted to the general hospital are presented. Several questions were addressed. First, the prevalence and associations of different types of self-harm were assessed. Second, the prevalence and associations of comorbid depressive disorder and substance abuse were examined. Third, shortterm suicide rates of suicide attempters and other consultation patients were calculated.
281 ISSN 0163-8343/00/$–see front matter PII S0163-8343(00)00085-2
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Methods Setting The psychiatric consultation service of the Department of Psychiatry at the University of South Alabama consists of two senior psychiatric residents under the supervision of faculty. Requests for consultation come from three university hospitals in Mobile, Alabama, i.e., two general hospitals and one children’s hospital. These facilities serve a predominantly indigenous population. None has psychiatric beds.
Procedures Records of consecutive psychiatric consultations in general hospital patients 15 years and older, between 1995 and 1998, were reviewed. Repeat consults on patients during the same admission were counted once and data were only taken from the last consultation report. Consultations done on the same patient but during different admissions were counted separately. Demographic and clinical data were recorded from copies of the consultation reports. Diagnostic information was classified in five categories, i.e., primary psychiatric disorder, substance abuse or substance related disorder, psychiatric disorder due to a general medical condition, no psychiatric disorder, and deferred diagnosis. Among the group with deliberate self-harm, six diagnostic groups based on DSM-IV criteria were differentiated, i.e., depressive disorder, substance abuse disorder, comorbid depressive and substance abuse disorder, adjustment disorder, schizophrenic disorder, and other disorder. Comorbid depressive and substance abuse disorders were defined as cases with substance abuse and depressive syndromes (major depression, dysthymia, atypical depression). Some cases also had comorbid anxiety disorders, but this group was not seen as a separate group as most of these patients were also diagnosed with depressive disorders. Consensus diagnoses on all cases were made in meetings of two reviewers, who scrutinized records separately, and a third independent reviewer. Self-harm was defined as any act resulting in physical harm requiring acute medical attention. Overdose was differentiated from other methods. Alcohol intoxication was not counted as self-harm unless there was evidence of suicidal intent. Deliberate self-harm (used synonymously with attempted suicide in this report) was defined as pur-
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poseful and intentional self-harm. Other cases were categorized as accidental self-harm or “unclear.” For example, if the patient claimed that an excess of sedatives was taken to treat insomnia, this was rated as accidental self-harm. Self-reported suicide intent was classified as low or high. If the patient said that he intended to kill himself at the time of self-harm, intent was rated as high. In other cases, patients said that they did not want to kill themselves but overdosed or selfinjured for a variety of reasons such as extreme anger, frustration, or agitation. Then, intent to die was rated as low. The consultation database was cross-referenced with a list of all suicides in Mobile county between 1995 and 1998. Suicide as the cause of death was determined by the Office of the Medical Examiner in Mobile.
Analyses The prevalence of self-harm in psychiatric consultations was assessed. Cases with accidental, deliberate, unclear, and no self-harm were compared. Diagnostic differences among suicide attempters were analyzed. T test and ANOVA were used for comparison of continuous variables (age), 2 analyses and Fisher’s Exact tests (when appropriate) for categorical variables. Variables that were significantly (P⬍.05) associated with the dependent variable (i.e., high and low suicide intent) in univariate analyses were entered in a step-wise logistic regression model to adjust for multivariate adjustment. The final model was accepted only if backward and forward elimination of variables yielded the same results. All analyses were done with SPSS 6.1 software for the Macintosh PC [11]. Probabilities less than 0.05 were considered significant.
Results There were 1136 patients referred for psychiatric consultation between 1995 and 1998: 482 (42%) were male, 682 (60%) were white, and the mean age was 41 (SD 17). Among 454 nonwhite patients, 442 were African-American and 12 had other racial backgrounds. Among the 1136 consultations, there were 371 cases with self-harm with 311 (84%) classified as deliberate, 44 (12%) as unclear, and 16 (4%) as accidental. In Table 1, it is shown that the mean age of the three groups with self-harm was lower than the
Suicide Attempts and Comorbid Depression, Substance Abuse
Table 1. Demographic and diagnostic variables in different types of self-harm in 1136 general hospital inpatients referred for psychiatric consultation between 1995 and 1998 Deliberate (n⫽311)
Agea Under 30 30–60 Over 60 Gender Male Female Race White Other Psychiatric diagnosisb Any functional disorder without comorbid substance abuse Any functional disorder comorbid with substance abuse Any disorder due to medical conditions None Deferred diagnosis
Accidental (n⫽16)
Unclear (n⫽44)
No self-harm (n⫽765)
n
%
n
%
n
%
n
%
120 183 8
39 59 3
6 10 0
38 62 0
20 23 1
46 52 2
153 444 168
20 58 22
129 182
42 58
8 8
50 50
19 25
43 57
326 439
43 57
199 112
64 36
8 8
50 50
32 12
73 27
443 322
58 42
163 143 2 3 0
52 46 1 1 0
6 6 0 4 0
37 38 0 25 0
23 14 3 3 1
52 32 7 7 2
296 142 212 101 14
39 19 28 13 2
a
P⬍.001. Mean age of those with deliberate self-harm was 33 (SD 12), with accidental self-harm 33 (SD 11), with unclear circumstances 32 (SD 13), and without self-harm 45 (SD 18) (t test; P⬍.05). b
P⬍.001.
mean age of the group without self-harm. Deliberate self-harm was found in 120 (40%) of 299 people under 30 compared with 183 (28%) of 660 between the ages 30 – 60 and 8 (5%) of 177 over 60. Gender and race distribution was not different between groups. In the group with deliberate self-harm (n⫽311), the female/male ratio was 1.5 across all age groups. Distribution of the diagnostic categories was different between types of self-harm (Table 1). Comorbid substance abuse disorders were found less frequently in the group without self-harm (19%) compared with the other groups (range 32–38%). Psychiatric conditions due to general medical conditions were diagnosed more often in the group without self-harm (28%) compared to the other groups (range 2–7%). The above findings were similar for all age groups and for males and females. In Table 2, demographic variables, method, and high versus low suicide intent are tabulated by diagnostic group (except the group with “other diagnoses”). Depressive disorders with and without substance abuse were diagnosed in 183 (59%) of 311 suicide attempters. Substance abuse disorders with and without depressive disorders were recorded in 143 (46%) of 311 cases. Substance abuse disorders
without depressive disorders (n⫽28, 9%), psychotic disorders (n⫽13, 4%), and a few less frequent diagnoses (n⫽8, 3%) were found less often. Comorbid depression and substance abuse was the most frequent specific diagnostic category (n⫽115, 37%). This was true in both genders, but only in the age group between 30 – 60. Adjustment disorder was the most frequent diagnosis in those under 30 (50 of 116; 43%). In the older group (over 60) depressive disorders were diagnosed in 3 (43%) of 7 cases. While the comorbid condition was the most frequent disorder by far in males (in 45% of males), female suicide attempters were diagnosed with depressive disorders without substance abuse (30%) about as often as with the comorbid condition (33%). Gender ratio and distribution of low and high suicide intent were different across diagnostic groups (Table 2). High suicide intent was found more frequently in the group with depressive disorders and comorbid disorders. Race and method were not associated with diagnosis. Overdose was the most frequent method in all diagnostic categories. There were 33 (11%) nonoverdose cases. The most frequent methods are shown in Table 3. Gunshots to the abdomen or
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Table 2. Comparison of suicide attempters (n⫽303) diagnosed with depressive disorders, comorbid substance abuse disorders and depression, substance abuse (alcohol/drug) disorders, adjustment disorders, and schizophrenic disorders
Agea Under 30 30–60 Over 60 Genderb Male Female Race White Other Method Overdose Gunshots Other Suicide intentc High Low
Depressive disorders (n⫽68)
Comorbid disorders (n⫽115)
Substance abuse disorders (n⫽28)
Adjustment disorders (n⫽79)
Schizophrenic disorders (n⫽13)
n
%
n
%
n
%
n
%
n
%
21 44 3
31 65 4
32 82 1
28 71 1
11 16 1
39 57 4
50 27 2
63 34 3
2 11 0
15 85 0
15b 53
22 78
58b 57
50 50
18 10
64 36
29 50
37 63
8 5
62 38
46 22
68 32
81 34
70 30
15 13
54 46
48 31
61 39
5 8
39 61
61 3 4
90 4 6
104 3 8
90 3 7
23 0 5
82 0 18
71 5 3
90 6 4
11 0 2
85 0 15
49 19
72 28
82 33
71 29
16 12
57 43
35 44
44 56
7 6
54 46
a
Age distribution was significantly different across diagnostic groups. The mean age of the group with adjustment disorders (28, SD 12) was different from the mean age of the other groups (P⬍.05). Mean age of those with depressive disorders was 35 (SD 14), with comorbid disorders 35 (SD 9), with alcohol/drug disorders 34 (SD 12), and with psychotic disorders 38 (SD 7). b Gender distribution was significantly different across diagnostic groups (P⬍.05). There were more females in the group with depressive disorders compared to all groups (except adjustment disorders). There were also more females in the group with adjustment disorders compared to the group with alcohol/drug and comorbid disorders. c Suicide intent was different between the group with mood disorders and comorbid disorders versus the group with adjustment disorders (P⬍.05).
Table 3. Diagnoses in suicide attempters who used non-overdose methods Depressive Comorbida Substance abuse Adjustment Schizophrenic disorders disorders disorders disorders disorders (n⫽6) (n⫽8) (n⫽5) (n⫽6) (n⫽2)
Firearms (n⫽11) Stabbing or cutting (n⫽6) Self-immolition (n⫽5) Jump from a height or in front of traffic (n⫽5) a b
n
n
n
n
n
3 1 1 1
3 2 2 1
0 3 1 1
5 0 1 0
0 0 0 2b
Comorbid depression and substance abuse disorder. One person with a psychotic disorder jumped from a height; the other ran into traffic.
extremities were found in seven cases, stabbing of neck or abdomen in five, self-immolition in five, gunshots to the head in four cases, and jumping from a height in three. Other methods were found
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only once or twice: going out in traffic (n⫽2), hanging (n⫽2), CO2 exhaust (n⫽2), swallowing of sharp objects (n⫽2), and wrist cutting in one. In Table 4, correlates of low and high suicide
Suicide Attempts and Comorbid Depression, Substance Abuse
Table 4. Comparison of groups with high and low suicide intent among 311 general hospital inpatients referred for psychiatric consultation due to suicide attempts High suicide intent (n⫽192)
Agea Under 30 30–60 Over 60 Genderb Male Female Race White Other Method Overdose Gunshot Other Psychiatric disorder (DO) Mood DOc Comorbid Dep/Subst DOd Substance abuse DO Adjustment DOe Schizophrenic DO Other DO
Low suicide intent (n⫽119)
n
%
n
%
62 125 5
32 65 3
58 58 3
49 49 2
90 102
47 53
39 80
33 67
123 69
64 36
76 43
64 36
167 10 15
87 5 8
111 1 7
93 1 6
49 82 16 35 7 3
25 43 8 18 4 2
19 33 12 44 6 5
16 28 10 37 5 4
a
P⬍.05. Mean age of the high intent group was 35 (SD 12) and of the low intent group 30 (SD 11) (T-test, p⬍0.0001). b
P⬍.05. P⫽.05. d P⬍.01. e P⬍.001. c
intent are shown. Suicide intent was associated with older age, male gender, and psychiatric diagnosis. Comorbid depression and substance abuse was the most frequent diagnosis in the group with high suicide intent. A diagnosis of adjustment disorder was associated with low suicide intent. To assess the possible confounding role of age and gender, two logistic regression models were tested with high versus low intent as the dependent variable and age, gender, and diagnosis (Presence versus absence of adjustment disorder in the first regression model; presence versus absence of comorbid disorder in the second model). Age, gender, and the two diagnoses remained significantly associated with intent, suggesting that all variables,
i.e., age, gender, and diagnosis (adjustment disorder and comorbid disorder) made independent contributions to explain the distribution of suicide intent across cases. Four suicides were found among psychiatric consultation patients by cross-referencing suicide and consultation databases between 1995 and 1998 (Table 5). The suicide rate for the suicide attempters (2 of 311) was 322 per 100,000 and 131 per 100,000 patient-years for psychiatric consultation patients (2 of 765) without self-harm.
Discussion Limitations and Strengths The study sample was limited to hospitalized suicide attempters, which suggests medical seriousness of the self-harm [12]. Many people with minor suicide attempts are not hospitalized [13] or never come to medical [14] or psychiatric [15] attention. Findings thus pertain to a selected group. Extrapolating results to less serious suicide attempts may not be possible. We believe that most acute suicide attempters admitted to the hospital were referred for psychiatric consultation and that the sample is representative of hospitalized suicide attempters, but we cannot present definite proof for this. We view the large sample size as a relative strength. The quality of a chart review is highly dependent on the written documentation of the consulting psychiatrists. It was found that most information that we sought was available in the charts. In some cases [n⫽44], the circumstances and intent of the self-harm were unclear (Table 1). We were not able to determine whether this was due to incomplete documentation or if the psychiatrist’s assessment was inconclusive. The “unclear” group was excluded from subsequent analyses. It is unlikely that this decision has altered findings as this group was very similar to the group with suicide attempts (Table 1). It is also useful to keep in mind that suicide attempters are a difficult research population. Studies with prospective designs often suffer low participation and high attrition rates. This was particularly evident in a recent multisite study on the epidemiology of attempted suicide with a mean participation rate of 47% with rates as low as 28% in certain sites [16]. The rates of substance abuse disorders may be underestimates as one may assume that some cases were missed. However, there is no a priori reason to believe that there was a bias between suicidal or
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Table 5. Characteristics of four suicides among 1136 psychiatric consultation patients at short-term follow-up between 1995 and 1998 Age, race, and gender 26-year-old 40-year-old 25-year-old 36-year-old
white male black male white female white male
Self-harm group
Diagnosis
Interval admission-suicide
Method of suicide
Suicide Attempta Suicide Attemptb No self-harm No self-harm
Schizophrenia Comorbid Dep/Subst Adjustment Disorder Deliriumc
3 months 5 months 7 months 29 months
Put head on train rail Self-immolition Overdose Gunshot
a
Jumped from bridge. Overdose. c Delirium due to general medical condition. b
non-suicidal cases. The problem of underdiagnosis probably does not invalidate the finding of higher rates of substance abuse in patients with self-harm, especially deliberate self-harm, compared to patients without self-harm. Our focus on comorbid depression and substance abuse may have obscured associations with other comorbid conditions such as anxiety disorders and personality disorders. The literature on the prevalence and importance of anxiety disorders in attempted suicide is inconsistent [17,18]. Findings on the high prevalence of personality disorders, especially borderline personality disorders, in suicide attempters and suicides are more robust [19,20]. These disorders were not addressed in this study. The relationship between depression and substance abuse is complex [21–23] and people that are diagnosed with both disorders probably constitute a heterogeneous group. Our findings support an association between suicide attempts and the group of people with both disorders. Further differentiation of the comorbid group was beyond the scope of this study. The suicide rates that we calculated may be underestimates due to short follow-up and incomplete ascertainment of suicides. Every death is not systematically examined for evidence of suicide, and every suicide may not be reported in order to protect the privacy of the family. In addition, some patients may have moved out of Mobile county before committing suicide. While it hard to estimate the impact of these factors, it seems safe to conclude that suicide rates were at least 20 times higher for suicide attempters and 10 times higher for psychiatric consultation patients than for the general population.
286
Prevalence and Associations of Comorbid Depression and Substance Abuse Comorbid depression and substance abuse was the most frequent individual diagnosis in suicide attempters. More males than females and more suicide attempters between ages 30 – 60 than from other age groups were diagnosed with this condition. The association between comorbid substance abuse and suicide attempts was found in both genders and in all age groups, however. These findings are consistent with reports that substance abuse disorders are common in male and adult psychiatric consultation patients [24] and that substance abuse disorders increase the risk for suicidal behavior regardless of age or gender [5]. It was found that increasing age, male gender, and a diagnosis of comorbid depression and substance abuse were associated with high suicide intent. Many, but not all studies, have also found that older people [10,25] and males [10] score higher on measures of suicide intent. In contrast with previous studies [10,25], method was not associated with intent. Although more suicide attempters with high suicide intent used non-overdose methods compared to those with low intent (13% versus 7%), this was not a significant difference. This may be due to the small number of non-overdose cases (11%) among suicide attempters in our study. Replication in other samples is warranted. Overall, findings suggest validity of self-reported intent as recorded from routine clinical notes. Direct comparisons with rating scales such as the Beck scale of suicide intent [9] or the intent scale described by Pierce [10] were not done as the consulting psychiatrists did not use these instruments at the time of the study. High suicide intent was often found in suicide attempters with comorbid depression and sub-
Suicide Attempts and Comorbid Depression, Substance Abuse
stance abuse. In a previous report [26], intent was not significantly different across diagnostic categories but comorbid disorders were not assessed. There are recent studies, however, supporting an increased level of suicidality in people with comorbid substance abuse. Petronis et al. [27] reported that active alcoholism and cocaine abuse were independent risk factors for attempting suicide during a 1- to 2-year follow-up period in the ECA surveys. Cornelius et al. [28] found that inpatients with comorbid major depression and alcoholism had higher levels of suicidality at admission compared to nonalcoholic patients with major depression and nondepressed alcoholics. Suicide attempters who were medically admitted versus those who were evaluated in the emergency room but not admitted were compared by Elliott et al. [12]. Suicide attempts followed by medical admission were associated with a diagnosis of substance-induced mood disorder. The authors suggest that mood dysfunction in the context of substance abuse is a risk factor for serious suicide attempts. In another study [29], various indices of substance abuse were associated with higher levels of suicidality in psychiatric inpatients with major depression. In psychiatric emergency room patients, toxicological detection of cocaine was associated with suicidality, especially in males [30]. Finally, there is strong evidence that the presence of a substance abuse disorder is an important risk factor for suicide [6 – 8]. Moreover, several authors have suggested that the increase in suicide rates in young people may be related to increased rates of substance abuse and substance related disorders [31,32]. In summary, findings in the current study support the association and possible causal relationship between combined depression and substance abuse and suicidal behavior.
Suicide Rates in Psychiatric Consultation Patients In line with other studies [33], the suicide risk in psychiatric consultation patients with and without suicide attempts was increased compared to the general population where the suicide rate is about 12 per 100,000. There was less than one year between consultation and suicide in three of four suicides. This suggests the possibility of suicide prevention in the general hospital setting. We are currently conducting a study on risk factors for suicide in general hospital patients. This issue remains challenging as suicide is a rare event even in high-risk groups.
Summary and Implications The evidence in this study supporting an association between suicide attempts and comorbid depression and substance abuse is twofold. First, comorbid disorders were more common in the group of suicide attempters compared to psychiatric consultation patients without suicide attempts. Second, there was a positive association between suicide intent and comorbid depression and substance abuse. Suicide attempters should be carefully assessed for comorbid substance abuse. The increased suicide rates in psychiatric consultation patients with and without suicide attempts warrant further research. We thank Charles L. Rich, M.D., Professor and Chair, Department of Psychiatry, University of South Alabama College of Medicine, and Leroy Riddick, M.D., Director of the Alabama Department of Forensic Sciences Mobile Regional Laboratory, for support.
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Introduction Psychiatric consultation is often requested for suicide attempters who are admitted to the general hospital. Some studies have suggested that it may be very difficult to prevent future attempts or suiDepartment of Psychiatry, University of South Alabama College of Medicine, Mobile, Alabama (D.M.D., A.M.M.), Department of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic, Pittsburgh, Pennsylvania (S.C.). Address reprint requests to: D.M. Dhossche, M.D., Reinpad Straat 98 Bus 12, 3600 Genk, Belgium.
General Hospital Psychiatry 22, 281–288, 2000 © 2000 Elsevier Science Inc. All rights reserved. 655 Avenue of the Americas, New York, NY 10010
cide [1], although psychiatric intervention is considered beneficial. Further study of this population may uncover new risk factors amenable to treatment or new markers for risk [2]. Alternatively, prevention of suicide may require broader changes in mental health care not limited to high-risk populations [3]. Suicide attempters are thought to be diagnostically heterogeneous with complicated psychosocial and psychiatric conditions as suggested by high comorbidity of psychiatric disorders, i.e., the co-occurrence of several disorders in one person [4,5]. There are several leads suggesting that substance abuse increases suicide risk [6 – 8]. Further examination of the role of comorbid substance abuse and other psychiatric disorders, especially depressive disorders, in suicidal behavior is warranted. Studies have supported the dimensional nature of intent to die in suicide attempters [9,10]. Clinicians routinely ask whether the patient with deliberate self-harm intended to die. This piece of information is often essential for treatment planning. Further studies on self-reported suicide intent are useful. In this study, findings in a new sample of suicide attempters admitted to the general hospital are presented. Several questions were addressed. First, the prevalence and associations of different types of self-harm were assessed. Second, the prevalence and associations of comorbid depressive disorder and substance abuse were examined. Third, shortterm suicide rates of suicide attempters and other consultation patients were calculated.
281 ISSN 0163-8343/00/$–see front matter PII S0163-8343(00)00085-2
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Methods Setting The psychiatric consultation service of the Department of Psychiatry at the University of South Alabama consists of two senior psychiatric residents under the supervision of faculty. Requests for consultation come from three university hospitals in Mobile, Alabama, i.e., two general hospitals and one children’s hospital. These facilities serve a predominantly indigenous population. None has psychiatric beds.
Procedures Records of consecutive psychiatric consultations in general hospital patients 15 years and older, between 1995 and 1998, were reviewed. Repeat consults on patients during the same admission were counted once and data were only taken from the last consultation report. Consultations done on the same patient but during different admissions were counted separately. Demographic and clinical data were recorded from copies of the consultation reports. Diagnostic information was classified in five categories, i.e., primary psychiatric disorder, substance abuse or substance related disorder, psychiatric disorder due to a general medical condition, no psychiatric disorder, and deferred diagnosis. Among the group with deliberate self-harm, six diagnostic groups based on DSM-IV criteria were differentiated, i.e., depressive disorder, substance abuse disorder, comorbid depressive and substance abuse disorder, adjustment disorder, schizophrenic disorder, and other disorder. Comorbid depressive and substance abuse disorders were defined as cases with substance abuse and depressive syndromes (major depression, dysthymia, atypical depression). Some cases also had comorbid anxiety disorders, but this group was not seen as a separate group as most of these patients were also diagnosed with depressive disorders. Consensus diagnoses on all cases were made in meetings of two reviewers, who scrutinized records separately, and a third independent reviewer. Self-harm was defined as any act resulting in physical harm requiring acute medical attention. Overdose was differentiated from other methods. Alcohol intoxication was not counted as self-harm unless there was evidence of suicidal intent. Deliberate self-harm (used synonymously with attempted suicide in this report) was defined as pur-
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poseful and intentional self-harm. Other cases were categorized as accidental self-harm or “unclear.” For example, if the patient claimed that an excess of sedatives was taken to treat insomnia, this was rated as accidental self-harm. Self-reported suicide intent was classified as low or high. If the patient said that he intended to kill himself at the time of self-harm, intent was rated as high. In other cases, patients said that they did not want to kill themselves but overdosed or selfinjured for a variety of reasons such as extreme anger, frustration, or agitation. Then, intent to die was rated as low. The consultation database was cross-referenced with a list of all suicides in Mobile county between 1995 and 1998. Suicide as the cause of death was determined by the Office of the Medical Examiner in Mobile.
Analyses The prevalence of self-harm in psychiatric consultations was assessed. Cases with accidental, deliberate, unclear, and no self-harm were compared. Diagnostic differences among suicide attempters were analyzed. T test and ANOVA were used for comparison of continuous variables (age), 2 analyses and Fisher’s Exact tests (when appropriate) for categorical variables. Variables that were significantly (P⬍.05) associated with the dependent variable (i.e., high and low suicide intent) in univariate analyses were entered in a step-wise logistic regression model to adjust for multivariate adjustment. The final model was accepted only if backward and forward elimination of variables yielded the same results. All analyses were done with SPSS 6.1 software for the Macintosh PC [11]. Probabilities less than 0.05 were considered significant.
Results There were 1136 patients referred for psychiatric consultation between 1995 and 1998: 482 (42%) were male, 682 (60%) were white, and the mean age was 41 (SD 17). Among 454 nonwhite patients, 442 were African-American and 12 had other racial backgrounds. Among the 1136 consultations, there were 371 cases with self-harm with 311 (84%) classified as deliberate, 44 (12%) as unclear, and 16 (4%) as accidental. In Table 1, it is shown that the mean age of the three groups with self-harm was lower than the
Suicide Attempts and Comorbid Depression, Substance Abuse
Table 1. Demographic and diagnostic variables in different types of self-harm in 1136 general hospital inpatients referred for psychiatric consultation between 1995 and 1998 Deliberate (n⫽311)
Agea Under 30 30–60 Over 60 Gender Male Female Race White Other Psychiatric diagnosisb Any functional disorder without comorbid substance abuse Any functional disorder comorbid with substance abuse Any disorder due to medical conditions None Deferred diagnosis
Accidental (n⫽16)
Unclear (n⫽44)
No self-harm (n⫽765)
n
%
n
%
n
%
n
%
120 183 8
39 59 3
6 10 0
38 62 0
20 23 1
46 52 2
153 444 168
20 58 22
129 182
42 58
8 8
50 50
19 25
43 57
326 439
43 57
199 112
64 36
8 8
50 50
32 12
73 27
443 322
58 42
163 143 2 3 0
52 46 1 1 0
6 6 0 4 0
37 38 0 25 0
23 14 3 3 1
52 32 7 7 2
296 142 212 101 14
39 19 28 13 2
a
P⬍.001. Mean age of those with deliberate self-harm was 33 (SD 12), with accidental self-harm 33 (SD 11), with unclear circumstances 32 (SD 13), and without self-harm 45 (SD 18) (t test; P⬍.05). b
P⬍.001.
mean age of the group without self-harm. Deliberate self-harm was found in 120 (40%) of 299 people under 30 compared with 183 (28%) of 660 between the ages 30 – 60 and 8 (5%) of 177 over 60. Gender and race distribution was not different between groups. In the group with deliberate self-harm (n⫽311), the female/male ratio was 1.5 across all age groups. Distribution of the diagnostic categories was different between types of self-harm (Table 1). Comorbid substance abuse disorders were found less frequently in the group without self-harm (19%) compared with the other groups (range 32–38%). Psychiatric conditions due to general medical conditions were diagnosed more often in the group without self-harm (28%) compared to the other groups (range 2–7%). The above findings were similar for all age groups and for males and females. In Table 2, demographic variables, method, and high versus low suicide intent are tabulated by diagnostic group (except the group with “other diagnoses”). Depressive disorders with and without substance abuse were diagnosed in 183 (59%) of 311 suicide attempters. Substance abuse disorders with and without depressive disorders were recorded in 143 (46%) of 311 cases. Substance abuse disorders
without depressive disorders (n⫽28, 9%), psychotic disorders (n⫽13, 4%), and a few less frequent diagnoses (n⫽8, 3%) were found less often. Comorbid depression and substance abuse was the most frequent specific diagnostic category (n⫽115, 37%). This was true in both genders, but only in the age group between 30 – 60. Adjustment disorder was the most frequent diagnosis in those under 30 (50 of 116; 43%). In the older group (over 60) depressive disorders were diagnosed in 3 (43%) of 7 cases. While the comorbid condition was the most frequent disorder by far in males (in 45% of males), female suicide attempters were diagnosed with depressive disorders without substance abuse (30%) about as often as with the comorbid condition (33%). Gender ratio and distribution of low and high suicide intent were different across diagnostic groups (Table 2). High suicide intent was found more frequently in the group with depressive disorders and comorbid disorders. Race and method were not associated with diagnosis. Overdose was the most frequent method in all diagnostic categories. There were 33 (11%) nonoverdose cases. The most frequent methods are shown in Table 3. Gunshots to the abdomen or
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Table 2. Comparison of suicide attempters (n⫽303) diagnosed with depressive disorders, comorbid substance abuse disorders and depression, substance abuse (alcohol/drug) disorders, adjustment disorders, and schizophrenic disorders
Agea Under 30 30–60 Over 60 Genderb Male Female Race White Other Method Overdose Gunshots Other Suicide intentc High Low
Depressive disorders (n⫽68)
Comorbid disorders (n⫽115)
Substance abuse disorders (n⫽28)
Adjustment disorders (n⫽79)
Schizophrenic disorders (n⫽13)
n
%
n
%
n
%
n
%
n
%
21 44 3
31 65 4
32 82 1
28 71 1
11 16 1
39 57 4
50 27 2
63 34 3
2 11 0
15 85 0
15b 53
22 78
58b 57
50 50
18 10
64 36
29 50
37 63
8 5
62 38
46 22
68 32
81 34
70 30
15 13
54 46
48 31
61 39
5 8
39 61
61 3 4
90 4 6
104 3 8
90 3 7
23 0 5
82 0 18
71 5 3
90 6 4
11 0 2
85 0 15
49 19
72 28
82 33
71 29
16 12
57 43
35 44
44 56
7 6
54 46
a
Age distribution was significantly different across diagnostic groups. The mean age of the group with adjustment disorders (28, SD 12) was different from the mean age of the other groups (P⬍.05). Mean age of those with depressive disorders was 35 (SD 14), with comorbid disorders 35 (SD 9), with alcohol/drug disorders 34 (SD 12), and with psychotic disorders 38 (SD 7). b Gender distribution was significantly different across diagnostic groups (P⬍.05). There were more females in the group with depressive disorders compared to all groups (except adjustment disorders). There were also more females in the group with adjustment disorders compared to the group with alcohol/drug and comorbid disorders. c Suicide intent was different between the group with mood disorders and comorbid disorders versus the group with adjustment disorders (P⬍.05).
Table 3. Diagnoses in suicide attempters who used non-overdose methods Depressive Comorbida Substance abuse Adjustment Schizophrenic disorders disorders disorders disorders disorders (n⫽6) (n⫽8) (n⫽5) (n⫽6) (n⫽2)
Firearms (n⫽11) Stabbing or cutting (n⫽6) Self-immolition (n⫽5) Jump from a height or in front of traffic (n⫽5) a b
n
n
n
n
n
3 1 1 1
3 2 2 1
0 3 1 1
5 0 1 0
0 0 0 2b
Comorbid depression and substance abuse disorder. One person with a psychotic disorder jumped from a height; the other ran into traffic.
extremities were found in seven cases, stabbing of neck or abdomen in five, self-immolition in five, gunshots to the head in four cases, and jumping from a height in three. Other methods were found
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only once or twice: going out in traffic (n⫽2), hanging (n⫽2), CO2 exhaust (n⫽2), swallowing of sharp objects (n⫽2), and wrist cutting in one. In Table 4, correlates of low and high suicide
Suicide Attempts and Comorbid Depression, Substance Abuse
Table 4. Comparison of groups with high and low suicide intent among 311 general hospital inpatients referred for psychiatric consultation due to suicide attempts High suicide intent (n⫽192)
Agea Under 30 30–60 Over 60 Genderb Male Female Race White Other Method Overdose Gunshot Other Psychiatric disorder (DO) Mood DOc Comorbid Dep/Subst DOd Substance abuse DO Adjustment DOe Schizophrenic DO Other DO
Low suicide intent (n⫽119)
n
%
n
%
62 125 5
32 65 3
58 58 3
49 49 2
90 102
47 53
39 80
33 67
123 69
64 36
76 43
64 36
167 10 15
87 5 8
111 1 7
93 1 6
49 82 16 35 7 3
25 43 8 18 4 2
19 33 12 44 6 5
16 28 10 37 5 4
a
P⬍.05. Mean age of the high intent group was 35 (SD 12) and of the low intent group 30 (SD 11) (T-test, p⬍0.0001). b
P⬍.05. P⫽.05. d P⬍.01. e P⬍.001. c
intent are shown. Suicide intent was associated with older age, male gender, and psychiatric diagnosis. Comorbid depression and substance abuse was the most frequent diagnosis in the group with high suicide intent. A diagnosis of adjustment disorder was associated with low suicide intent. To assess the possible confounding role of age and gender, two logistic regression models were tested with high versus low intent as the dependent variable and age, gender, and diagnosis (Presence versus absence of adjustment disorder in the first regression model; presence versus absence of comorbid disorder in the second model). Age, gender, and the two diagnoses remained significantly associated with intent, suggesting that all variables,
i.e., age, gender, and diagnosis (adjustment disorder and comorbid disorder) made independent contributions to explain the distribution of suicide intent across cases. Four suicides were found among psychiatric consultation patients by cross-referencing suicide and consultation databases between 1995 and 1998 (Table 5). The suicide rate for the suicide attempters (2 of 311) was 322 per 100,000 and 131 per 100,000 patient-years for psychiatric consultation patients (2 of 765) without self-harm.
Discussion Limitations and Strengths The study sample was limited to hospitalized suicide attempters, which suggests medical seriousness of the self-harm [12]. Many people with minor suicide attempts are not hospitalized [13] or never come to medical [14] or psychiatric [15] attention. Findings thus pertain to a selected group. Extrapolating results to less serious suicide attempts may not be possible. We believe that most acute suicide attempters admitted to the hospital were referred for psychiatric consultation and that the sample is representative of hospitalized suicide attempters, but we cannot present definite proof for this. We view the large sample size as a relative strength. The quality of a chart review is highly dependent on the written documentation of the consulting psychiatrists. It was found that most information that we sought was available in the charts. In some cases [n⫽44], the circumstances and intent of the self-harm were unclear (Table 1). We were not able to determine whether this was due to incomplete documentation or if the psychiatrist’s assessment was inconclusive. The “unclear” group was excluded from subsequent analyses. It is unlikely that this decision has altered findings as this group was very similar to the group with suicide attempts (Table 1). It is also useful to keep in mind that suicide attempters are a difficult research population. Studies with prospective designs often suffer low participation and high attrition rates. This was particularly evident in a recent multisite study on the epidemiology of attempted suicide with a mean participation rate of 47% with rates as low as 28% in certain sites [16]. The rates of substance abuse disorders may be underestimates as one may assume that some cases were missed. However, there is no a priori reason to believe that there was a bias between suicidal or
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Table 5. Characteristics of four suicides among 1136 psychiatric consultation patients at short-term follow-up between 1995 and 1998 Age, race, and gender 26-year-old 40-year-old 25-year-old 36-year-old
white male black male white female white male
Self-harm group
Diagnosis
Interval admission-suicide
Method of suicide
Suicide Attempta Suicide Attemptb No self-harm No self-harm
Schizophrenia Comorbid Dep/Subst Adjustment Disorder Deliriumc
3 months 5 months 7 months 29 months
Put head on train rail Self-immolition Overdose Gunshot
a
Jumped from bridge. Overdose. c Delirium due to general medical condition. b
non-suicidal cases. The problem of underdiagnosis probably does not invalidate the finding of higher rates of substance abuse in patients with self-harm, especially deliberate self-harm, compared to patients without self-harm. Our focus on comorbid depression and substance abuse may have obscured associations with other comorbid conditions such as anxiety disorders and personality disorders. The literature on the prevalence and importance of anxiety disorders in attempted suicide is inconsistent [17,18]. Findings on the high prevalence of personality disorders, especially borderline personality disorders, in suicide attempters and suicides are more robust [19,20]. These disorders were not addressed in this study. The relationship between depression and substance abuse is complex [21–23] and people that are diagnosed with both disorders probably constitute a heterogeneous group. Our findings support an association between suicide attempts and the group of people with both disorders. Further differentiation of the comorbid group was beyond the scope of this study. The suicide rates that we calculated may be underestimates due to short follow-up and incomplete ascertainment of suicides. Every death is not systematically examined for evidence of suicide, and every suicide may not be reported in order to protect the privacy of the family. In addition, some patients may have moved out of Mobile county before committing suicide. While it hard to estimate the impact of these factors, it seems safe to conclude that suicide rates were at least 20 times higher for suicide attempters and 10 times higher for psychiatric consultation patients than for the general population.
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Prevalence and Associations of Comorbid Depression and Substance Abuse Comorbid depression and substance abuse was the most frequent individual diagnosis in suicide attempters. More males than females and more suicide attempters between ages 30 – 60 than from other age groups were diagnosed with this condition. The association between comorbid substance abuse and suicide attempts was found in both genders and in all age groups, however. These findings are consistent with reports that substance abuse disorders are common in male and adult psychiatric consultation patients [24] and that substance abuse disorders increase the risk for suicidal behavior regardless of age or gender [5]. It was found that increasing age, male gender, and a diagnosis of comorbid depression and substance abuse were associated with high suicide intent. Many, but not all studies, have also found that older people [10,25] and males [10] score higher on measures of suicide intent. In contrast with previous studies [10,25], method was not associated with intent. Although more suicide attempters with high suicide intent used non-overdose methods compared to those with low intent (13% versus 7%), this was not a significant difference. This may be due to the small number of non-overdose cases (11%) among suicide attempters in our study. Replication in other samples is warranted. Overall, findings suggest validity of self-reported intent as recorded from routine clinical notes. Direct comparisons with rating scales such as the Beck scale of suicide intent [9] or the intent scale described by Pierce [10] were not done as the consulting psychiatrists did not use these instruments at the time of the study. High suicide intent was often found in suicide attempters with comorbid depression and sub-
Suicide Attempts and Comorbid Depression, Substance Abuse
stance abuse. In a previous report [26], intent was not significantly different across diagnostic categories but comorbid disorders were not assessed. There are recent studies, however, supporting an increased level of suicidality in people with comorbid substance abuse. Petronis et al. [27] reported that active alcoholism and cocaine abuse were independent risk factors for attempting suicide during a 1- to 2-year follow-up period in the ECA surveys. Cornelius et al. [28] found that inpatients with comorbid major depression and alcoholism had higher levels of suicidality at admission compared to nonalcoholic patients with major depression and nondepressed alcoholics. Suicide attempters who were medically admitted versus those who were evaluated in the emergency room but not admitted were compared by Elliott et al. [12]. Suicide attempts followed by medical admission were associated with a diagnosis of substance-induced mood disorder. The authors suggest that mood dysfunction in the context of substance abuse is a risk factor for serious suicide attempts. In another study [29], various indices of substance abuse were associated with higher levels of suicidality in psychiatric inpatients with major depression. In psychiatric emergency room patients, toxicological detection of cocaine was associated with suicidality, especially in males [30]. Finally, there is strong evidence that the presence of a substance abuse disorder is an important risk factor for suicide [6 – 8]. Moreover, several authors have suggested that the increase in suicide rates in young people may be related to increased rates of substance abuse and substance related disorders [31,32]. In summary, findings in the current study support the association and possible causal relationship between combined depression and substance abuse and suicidal behavior.
Suicide Rates in Psychiatric Consultation Patients In line with other studies [33], the suicide risk in psychiatric consultation patients with and without suicide attempts was increased compared to the general population where the suicide rate is about 12 per 100,000. There was less than one year between consultation and suicide in three of four suicides. This suggests the possibility of suicide prevention in the general hospital setting. We are currently conducting a study on risk factors for suicide in general hospital patients. This issue remains challenging as suicide is a rare event even in high-risk groups.
Summary and Implications The evidence in this study supporting an association between suicide attempts and comorbid depression and substance abuse is twofold. First, comorbid disorders were more common in the group of suicide attempters compared to psychiatric consultation patients without suicide attempts. Second, there was a positive association between suicide intent and comorbid depression and substance abuse. Suicide attempters should be carefully assessed for comorbid substance abuse. The increased suicide rates in psychiatric consultation patients with and without suicide attempts warrant further research. We thank Charles L. Rich, M.D., Professor and Chair, Department of Psychiatry, University of South Alabama College of Medicine, and Leroy Riddick, M.D., Director of the Alabama Department of Forensic Sciences Mobile Regional Laboratory, for support.
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