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Gender Differences in Suicide Attempts From Adolescence to Young Adulthood
Gender Differences in Suicide Attempts From Adolescence to Young Adulthood PETER M. LEWINSOHN, PH.D., PAUL ROHDE, PH.D., JOHN R. SEELEY, M.S., AND CAROL L. BALDWIN, PH.D.
ABSTRACT Objective: To examine associations of age, gender, and psychosocial factors during adolescence with risk of suicide attempt between ages 19 and 23 years. Method: Initial assessments were conducted with 1,709 adolescents (aged 14–18) in western Oregon between 1987 and 1989. One year later, 1,507 participants returned for a second assessment. A subset of participants (n = 941; 57.2% women) had a third diagnostic assessment after turning 24 (between 1993 and 1999). Information on suicidal behavior, psychosocial risk factors, and lifetime DSM-III-R psychiatric diagnosis was collected at each assessment. Results: The suicide attempt hazard rate for female adolescents was significantly higher than for male adolescents (Wilcoxon χ21[n = 941] = 12.69, p < .001). By age 19, the attempt hazard rate for female adolescents dropped to a level comparable with that of male adolescents. Disappearance of the gender difference for suicide attempts by young adulthood was not paralleled by a decrease in the gender difference for major depression. Adolescent suicidal behavior predicted suicide attempt during young adulthood for female, but not male, participants. Adolescent psychosocial risk factors for suicide attempt during young adulthood were identified separately for girls and boys. Conclusions: Unlike depression, the elevated incidence rate of suicide attempts by adolescent girls is not maintained into young adulthood. Screening and prevention implications are discussed. J. Am. Acad. Child Adolesc. Psychiatry, 2001, 40(4):427–434. Key Words: suicide attempt, gender, age, major depression.
Adolescent suicide attempts are an important public health problem. Rates of both suicide attempts and completions by adolescents have increased since the 1960s (Centers for Disease Control, 2000; Rosenberg et al., 1987; Wexler et al., 1978), and suicide is currently the third leading cause of mortality among 15- to 24-year-olds (National Vital Statistics Report, 1999). Recent epidemiological studies suggest that the lifetime rate of suicide attempts among high school students ranges from 3% to 15% (Centers for Disease Control, 2000; Lewinsohn et al., 1994; Shaffer and Hicks, 1992). Although the majority of these attempts are of low medical lethality (Lewinsohn et al., 1996), having made a past suicide attempt is the strongest predictor of both future suicide attempts and completions (Hawton, 1992; Shaffer and Hicks, 1992). Accepted November 7, 2000. From the Oregon Research Institute, Eugene. This research was supported in part by NIMH awards MH40501, MH50522, and MH52858. Reprint requests to Dr. Lewinsohn, Oregon Research Institute, 1715 Franklin Blvd., Eugene, OR 97403-1983; e-mail: [email protected]. 0890-8567/01/4004-0427䉷2001 by the American Academy of Child and Adolescent Psychiatry.
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Marked developmental trends exist in the frequency of suicide attempts. Attempts before adolescence are extremely rare, but a sharp increase occurs during early adolescence (13–18 years of age), followed by an apparent decrease as adolescents enter early adulthood (Lewinsohn et al., 1996; see also Garrison et al., 1993; Hawton, 1992; Shaffer and Hicks, 1992). Nearly all of these investigations, however, were based on cross-sectional and lifetime retrospective reports. In this article, we report the results of a prospective study of community young adults who were originally assessed during high school (Lewinsohn et al., 1993). The first goal of the present study was to describe the pattern of suicide attempts from childhood through 23 years of age separately for male and female participants. To our knowledge, a fine-grained analysis of the relationships between age, gender, and suicide attempts between adolescence and young adulthood has yet to be conducted. Gender differences in suicidal behavior are known to exist. Although rates of completed suicide are higher for men in both adolescence and adulthood (Meehan et al., 1992; Shaffer and Hicks, 1992) rates of suicide attempt are two to three times greater for female adolescents 427
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compared with male adolescents (Lewinsohn et al., 1996; see also Hawton, 1992; Kessler and McRae, 1983; Weissman, 1974; Wexler et al., 1978). Several explanations for this “gender paradox” have been proposed (Canetto, 1998; Moscicki, 1994), including gender differences in the lethality of suicide attempt methods, accuracy and honesty in reporting of past suicidal behavior, frequency of depression versus substance use disorders, and socialization regarding culturally acceptable forms of self-destructive behaviors. No single explanation appears to adequately account for these differences. One possible explanation for the elevated rate of suicide attempts among young women is their elevated rate of depression (Lewinsohn et al., 1993; see also Kessler et al., 1993). Suicidal behavior (i.e., ideation and attempts) is an important symptom of major depressive disorder (MDD) as per the DSM-IV, and research has repeatedly shown associations between depression and suicidal behavior in both adolescents and adults (Brent et al., 1993; Garrison et al., 1991; Harrington et al., 1994; Kovacs et al., 1993; Marttunen et al., 1991; Petronis et al., 1990). The second goal of this study was to superimpose associations between age, gender, and suicide attempt onto comparable associations between age, gender, and MDD. To what extent does the gender ratio for suicide attempts parallel the gender ratio for MDD from adolescence to young adulthood? This study also examines the extent to which suicidal behavior and other psychosocial risk factors that predict adolescent suicide attempts act as risk factors for suicide attempts in young adulthood. We previously found (Lewinsohn et al., 1994) that prior suicide attempts and suicidal ideation, depression, negative cognitions, low self-esteem, low social support from family, and difficulty climbing stairs as a result of physical illness were among the strongest predictors of future suicide attempts 1 year later in adolescence. In the present study, we examined whether these risk factors are influential over a much longer time interval. The present study is one in a series of reports from the Oregon Adolescent Depression Project (OADP), which is based on a large, randomly selected cohort of high school students who were assessed at two points over a period of 1 year (T1 and T2) by means of rigorous diagnostic criteria and structured diagnostic interviews. Recently, a large subset of OADP participants completed a third (T3) interview after their 24th birthday. Data regarding suicide attempts were obtained at all diagnostic assessments. 428
METHOD Participants OADP participants were randomly selected from nine senior high schools in western Oregon. A total of 1,709 adolescents (ages 14–18) completed the initial (T1) assessments (interview and questionnaires) between 1987 and 1989, with an overall participation rate of 61%. At the second assessment (T2), 1,507 participants (88%) returned for a readministration of the interview and questionnaire (mean T1–T2 interval = 13.8 months, SD = 2.3). Differences between the sample and the larger population from which it was selected, and between participants and those who declined to participate or dropped out of the study, were small (additional details regarding the T1 and T2 assessments are provided by Lewinsohn et al., 1993). After individuals reached their 24th birthday (between 1993 and 1999), all participants with a history of MDD at T2 (n = 360), those with a history of other psychopathology at T2 (n = 284), and a subset of participants with no history of mental disorder at T2 (n = 457) were invited to participate in a T3 interview. Sampling of the no-disorder comparison group was proportional to age, and gender within age; all participants with nonwhite ethnicity were invited to participate in the T3 assessments. Of the 1,101 individuals selected for T3 interview, 941 young adults (85%) participated (57% female; average T3 age = 24.2 years, SD = 0.6; 89% white; 34% married; 97% graduated from high school; 31% received a bachelor’s degree or higher). Women were more likely than men to complete the T3 assessments (89% versus 81%; χ21[n = 1,101] = 13.55, p < .001). Differences in T3 participation as a function of other demographics or T2 diagnostic status were nonsignificant. Those with a history of suicide attempt at T2 were more likely than nonattempters to complete the T3 assessments (93% versus 84%; χ21[n = 1,101] = 5.02, p < .05). Diagnostic Interviews Participants were interviewed at T1 with a version of the Schedule for Affective Disorders and Schizophrenia for School-Age Children (K-SADS), which combined features of the Epidemiologic version (Orvaschel et al., 1982) and the Present Episode version and included additional items to derive DSM-III-R diagnoses. At T2 and T3, participants were interviewed with the Longitudinal Interval Followup Evaluation (LIFE) (Keller et al., 1987), in combination with the K-SADS. (The LIFE procedure was used to track the course of preexisting disorders and to probe for the development of new disorders; when they occurred, symptoms and characteristics of new disorders in the follow-up period were assessed with relevant sections of the K-SADS.) This combined procedure elicited detailed information about the course of psychiatric symptoms and disorders, including suicidal behavior since the previous interview. T3 diagnoses were made with the LIFE/K-SADS methodology, revised for DSM-IV criteria. Diagnostic interviewers were carefully selected and trained; most interviewers held advanced degrees in clinical psychology, counseling psychology, or social work, and all of them completed an experiential course in diagnostic interviewing. After interviews were completed, diagnostic packets were carefully reviewed by supervisors for completion and accuracy. On the basis of a randomly selected subsample of participants at T1 and T2 (n = 233), interrater reliability for lifetime diagnoses were moderate to excellent: MDD (κ = 0.86), dysthymia (κ = 0.58), bipolar disorder (κ = 0.49), anxiety disorder (κ = 0.76), disruptive behavior disorders (κ = 0.83), alcohol abuse/dependence (κ = 0.84), and drug abuse/dependence (κ = 0.84). During the T2–T3 period, interrater reliability for the diagnosis of MDD in a review of
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178 randomly selected interviews was excellent (κ = 0.87). In the T3 sample (in which participants with past psychopathology were overrepresented), 455 (48.5%) had no history of MDD, 283 (30.1%) had one lifetime episode of MDD, and 202 (21.5%) had multiple episodes of MDD. Assessment of Suicidal Behavior Information on suicidal behavior was collected with similar probes at each of the three interviews. The operational definition of suicidal ideation was based on endorsement of at least one of three questions from the K-SADS (thoughts of death or dying, wishing to be dead, or thinking about hurting or killing oneself ). The operational definition of a suicide attempt was a positive response to the question, “Have you ever (or “since the last interview”) tried to kill yourself or done anything that could have killed you,” followed by additional probes to eliminate purely thrill-seeking behaviors and to determine the person’s age at the time of the attempt. Interrater reliability for a suicide attempt was excellent at T1 (κ = 0.95, n = 213); interrater reliability was not available at T2 and T3 because of the low number of suicide attempts in the reliability sample. Of the T3 participants, 816 (86.7%) had no history of suicide attempts, 72 (7.7%) reported one attempt, and 52 (5.5%) reported multiple attempts. Psychosocial Measures An extensive battery of psychosocial measures was administered to all participants at T1. All measures had been previously shown to posses very good psychometric properties (Andrews et al., 1993; Lewinsohn et al., 1993). Variables were standardized and scored such that higher values reflected more problematic functioning. In a previous report (Lewinsohn et al., 1994), we identified a set of 18 psychosocial variables that were significant risk factors for making a suicide attempt during adolescence (i.e., from T1 to T2), which were examined in the present study as predictors of suicide attempt from T2 to T3. Negative cognitions were assessed with 27 items that concern selfreinforcement, likelihood of future positive events, dysfunctional attitudes, and perceived control over one’s life (α = .81). Attributional style was assessed with the 48-item Kastan Attributional Style Questionnaire for Children (α = .63) (N. Kaslow et al., unpublished, 1978). Self-esteem was assessed with 9 items regarding physical appearance and general self-esteem (α = .81). Excessive emotional reliance was assessed with 10 items that examine the extent to which individuals desire excessive support and approval from others and are interpersonally sensitive (α = .83) (Hirschfeld et al., 1976). Self-consciousness was assessed with 9 items from the Self-Consciousness Scale (α = .74) (Fenigstein et al., 1975). Social self-competence was assessed with 12 items (α = .85). Coping skills were assessed with 17 items (α = .76). Social support: Friends was assessed with 13 items (α = .81). Social support: Family was assessed with 22 items (α = .86). Daily hassles were assessed with 20 items from the Unpleasant Events Schedule (α = .79) (Lewinsohn et al., 1985). Major life events were assessed with 14 events from the Schedule of Recent Experience (Holmes and Rahe, 1967) and the Life Events Schedule (Sandler and Block, 1979), rated for occurrence to self or significant others in the past year (α = .78). The following single item measures were also included: teenage mother (i.e., mother was less than 20 years of age at the time of the participant’s birth); parental education (i.e., bachelor’s degree obtained by either parent); Beck Depression Inventory Hopelessness item (Beck et al., 1961); suicide attempt by friend in the past year; problems with appetite (rated on a four-point scale); difficulties with climbing stairs and difficulties with activities in the past year because of illness or injury.
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Psychopathology Before Age 19 On the basis of the K-SADS interviews conducted at T1, T2, and T3, incidence of the following psychiatric disorders occurring before 19 years of age were included as predictor variables: MDD (n = 328), dysthymia (n = 43), bipolar disorder (n = 18), anxiety disorders (n = 160), conduct/oppositional disorders (n = 77), attention-deficit/hyperactivity disorder (n = 34), alcohol abuse/dependence (n = 156), drug abuse/dependence (n = 151), and eating disorders (n = 21). Data Analysis Life table survival methods were used to calculate annual hazard rates for suicide attempt and for MDD; calculations were based on 2year intervals from birth through age 24. Analyses were conducted with two samples: (1) all T1 participants, with those who did not participate at T2 or T3 and who did not experience an event (i.e., suicide attempt or major depression episode) being censored at their last observation point; and (2) only T3 participants. Given the comparability of results, data from the T3 participants are presented. Contingency tables and logistic regression analysis were used to test gender differences in period prevalence rates and to test prospective associations between suicidal behavior, psychosocial risk factors, and psychopathology. Alpha was set to p < .05, two-tailed, for χ2 tests and odds ratios (ORs). Because participants without a history of psychopathology at T2 were undersampled at T3, both observed and weighted rates are reported. RESULTS Suicide Attempt Rates From Childhood to Young Adulthood
Annual hazard rates in 2-year intervals for first suicide attempts for female and male participants from childhood to young adulthood are shown in the upper portion of Figure 1. Each interval shown in the figure contains the annual hazard rates for that year of age and the preceding year (e.g., the interval labeled “14” consists of the average hazard rates for ages 13 and 14). The survival curves for the two genders were significantly different (Wilcoxon χ21[n = 941] = 12.69, p < .001). As can be seen, beginning at age 13, the suicide attempt annual hazard rates increase rapidly for girls, who are at elevated risk between the ages of 15 and 18. The annual hazard rate for women decreases during the period of 19 to 23 years of age. Rates of first attempt for boys reach their highest levels at age 15 and are maintained until age 20. By age 19, the hazard rates for both genders are quite similar. For comparison purposes, annual hazard rates for the first incidence of MDD as a function of gender are shown in the lower portion of the figure. Significant differences were present in MDD hazard rate curves for male and female participants (Wilcoxon χ21[n = 941] = 61.15, p < .001). MDD rates for both genders increased markedly by age 15, with the hazard rate for girls approximately twice that of boys. In contrast to the suicide attempt haz429
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Fig. 1 Annual hazard rates for first episode of suicide attempt (SA) and major depressive disorder (MDD) as a function of gender.
ard rates, however, the hazard rates for MDD do not significantly decrease in young adulthood for either gender. Period prevalence rates of suicide attempt were examined in three developmental periods (1) childhood, defined as ages 5 to 11, (2) adolescence, defined as ages 12 to 18, and (3) young adulthood, defined as ages 19 to 23. The percentage of female and male participants who had made a suicide attempt (first or recurrent) in each of the three time periods was contrasted; results are shown in Table 1. Even though five of the six children who made an attempt were girls, this difference was not statistically significant. In adolescence, female participants had a significantly higher rate of suicide attempts compared with male participants. The gender difference did not attain statistical significance during young adulthood. Also shown in Table 1 are the percentages of male and female participants who experienced an episode of MDD (first or recurrent) during the three developmental periods. Significant gender differences in MDD occurrence were present for all three periods, with female participants having consistently higher rates than male participants.
TABLE 1 Gender Differences in Suicide Attempt and Major Depressive Disorder During Childhood, Adolescence, and Young Adulthood Outcome/Time Period Suicide attempt (%) 5–11 years of age Observeda Weightedb 12–18 years of age Observed Weighted 19–23 years of age Observed Weighted Occurrence of MDD (%) 5–11 years of age Observed Weighted 12–18 years of age Observed Weighted 19–23 years of age Observed Weighted
Female Sample
Male Sample
χ2
0.9 0.8
0.2 0.2
1.88 3.12
12.8 9.9
6.0 4.2
3.7 3.2
2.5 1.8
6.9 5.1
1.7 1.2
15.22*** 17.97***
4.16 (1.83–9.43) 4.61 (2.04–10.41)
40.1 30.2
21.1 14.8
39.00*** 44.95***
2.49 (1.86–3.35) 2.49 (1.89–3.29)
36.5 33.8
19.7 16.9
32.64*** 50.03***
2.36 (1.74–3.19) 2.51 (1.93–3.27)
12.70*** 16.68*** 1.12 2.44
OR (95% CI)
3.78 5.03
(0.43–32.26) (0.60–41.98)
2.31 (1.43–3.75) 2.53 (1.58–4.04) 1.51 (0.70–3.26) 1.77 (0.86–3.67)
Note: OR = odds ratio; CI = confidence interval; MDD = major depressive disorder. a df = 1, N = 941. b df = 1, N = 1,320. *** p < .001.
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Association Between Adolescent Suicidal Behavior and Suicide Attempt During Young Adulthood
To examine the association between suicidal behavior during childhood/adolescence and suicide attempt during young adulthood, and to test for moderating effects of gender, a hierarchical logistic regression analysis was conducted to predict suicide attempt in young adulthood. The first block included history of suicidal behavior (either suicide ideation or attempt) before age 19 and gender. The second block included the interaction term between suicidal behavior and gender. A significant main effect was obtained for adolescent suicidal behavior (likelihood ratio: χ21[n = 941] = 14.40, p < .001; OR = 4.26, 95% confidence interval [CI] = 1.98–9.11), but not for gender. However, the two-way interaction between gender and adolescent suicide behavior significantly improved the model fit (likelihood ratio: χ21[n = 941] = 3.89, p < .05). To interpret the significant interaction, the association between adolescent suicide behavior and suicide attempt during young adulthood was examined separately by gender. Compared with female participants who did not attempt suicide in young adulthood (n = 519), young adult female attempters (n = 20) had elevated rates of suicide ideation (80% versus 31%; OR = 8.81, 95% CI = 2.90–26.78) and suicide attempt (35% versus 13%; OR = 3.63, 95% CI = 1.40–9.43) during adolescence. In contrast, young adult male attempters (n = 10) did not differ significantly from male nonattempters (n = 392) with respect to suicide ideation (30% versus 20%, OR = 1.67, 95% CI = 0.42–6.61) and suicide attempt (0% versus 6%; OR = not calculable) during adolescence. Thus, continuity in suicidal behavior was obtained only for female participants. Prediction of Suicide Attempt in Young Adulthood
In a previous report (Lewinsohn et al., 1994), we identified a set of psychosocial risk factors for making a suicide attempt during adolescence (i.e., between T1 and T2). To examine the extent to which these risk factors predicted a suicide attempt in the 19–23 year period, hierarchical logistic regression analyses were conducted. In addition to the psychosocial risk factors, history of psychopathology before age 19 was included in the model. Given the significant gender difference obtained for the association between adolescent suicidal behavior and suicide attempt during young adulthood, the models were tested separately by gender. Because the participants varied in age (range 14–18 years) at the time of the T1 J . A M . A C A D . C H I L D A D O L E S C . P S YC H I AT RY, 4 0 : 4 , A P R I L 2 0 0 1
assessment, age was included as a covariate in the analyses. The mean score or proportion for attempters and nonattempters, along with the ORs for making an attempt in young adulthood, are presented in Table 2. As can be seen, the significant predictors for female participants include negative cognitions, low self-esteem, excessive emotional reliance on others, poor coping skills, low social support from family, and a history of MDD before age 19. For male participants, the significant predictors include negative cognitions, depressotypic attributional style, poor coping skills, low social support from friends, and a history of MDD before age 19. Summary logistic regression models were tested on the set of significant predictors for each gender with the likelihood ratio backward deselection procedure. Because suicide ideation and attempt before age 19 were significantly associated with a suicide attempt in young adulthood for female participants, they were also included in the model. Of the eight significant predictors of suicide attempts by young women, only previous suicide ideation was retained in the model (likelihood ratio: χ21[n = 539] = 14.19, p < .001). For male participants, of the five significant predictors, only poor coping skills was retained in the model (likelihood ratio: χ21[n = 402]= 5.64, p < .05). DISCUSSION
Several somewhat unexpected findings are noteworthy. First, without disaggregating results for male and female participants, we would have erroneously concluded that the suicide attempt rate decreases from adolescence to young adulthood. In fact, a significant drop in hazard rate is evident only for young women. Future research needs to examine whether annual hazard rates remain at this low level as the participants move further into adulthood. Disappearance of the gender difference for suicide attempts by young adulthood is not accounted for by a parallel decrease in the gender difference for MDD. Female gender is significantly associated with MDD in each of the three developmental periods, with an OR greater than 2.0 in each time period. Research to identify factors that account for the high rate of depression in girls beginning at a very early age deserves a high priority. Similarly, research to explain the high rate of suicide attempt in female adolescents and the decline in the suicide attempt rate in young women is needed. Suicidal behavior (ideation or attempt) during childhood and adolescence predicted a suicide attempt during 431
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TABLE 2 Psychosocial and Psychopathological Predictors of Suicide Attempt in Young Adulthood Female Sample (n = 539) Variable Psychosocial Negative cognitions: M (SD) Attributional style: M (SD) Self-esteem: M (SD) Emotional reliance: M (SD) Self-consciousness: M (SD) Social self-competence: M (SD) Coping skills: M (SD) Friend support: M (SD) Family support: M (SD) Daily hassles: M (SD) Major events: M (SD) BDI Hopelessness: M (SD) Problems with appetite: M (SD) Teenage mother (%) Parental education (%) Attempt by friend (%) Difficulty climbing stairs (%) Difficulty with activities (%) Psychopathology Major depression (%) Dysthymia (%) Bipolar disorder (%) Anxiety disorder (%) Conduct/oppositional (%) Attention deficit (%) Alcohol abuse/dependence (%) Drug abuse/dependence (%) Eating disorder (%)
Attempter (n = 20) 0.55 0.28 0.54 0.44 0.27 0.40 0.50 0.37 0.67 0.07 0.31 0.27 0.34 15.0 75.0 5.0 5.0 15.0 70.0 5.0 5.0 30.0 10.0 0.0 25.0 25.0 0.0
(0.92) (0.77) (0.97) (1.01) (1.05) (1.32) (1.00) (1.55) (0.88) (1.23) (0.98) (1.17) (1.19)
Nonattempter (n = 519) –0.02 –0.01 –0.02 –0.02 –0.01 –0.02 –0.02 –0.01 –0.03 0.00 –0.01 –0.01 –0.01 11.5 56.6 17.7 2.8 18.5
(1.00) (1.01) (0.98) (1.00) (1.00) (0.98) (1.00) (0.97) (1.00) (0.99) (1.00) (0.99) (0.99)
43.2 5.4 2.1 21.8 4.8 2.1 13.5 12.9 3.7
OR (95% CI) 2.12 1.40 2.11 1.07 1.06 2.13 1.07 1.77 2.69 1.01 1.05 1.45 1.52 1.53 2.26 0.25 2.06 0.89 3.04 0.90 2.50 1.57 2.31
Male Sample (n = 402) Attempter (n = 10)
(1.18–3.81) 0.68 (1.17) (0.85–2.31) 0.65 (0.86) (1.16–3.85) 0.50 (0.87) (1.01–1.15) 0.41 (1.13) (0.97–1.16) 0.55 (0.91) (0.95–4.77) 0.52 (0.99) (1.01–1.13) 0.74 (0.88) (0.92–3.40) 0.64 (1.06) (1.41–5.13) 0.05 (1.08) (0.97–1.04) 0.50 (0.81) (0.98–1.12) –0.27 (0.76) (0.78–2.68) 0.14 (0.93) (0.88–2.64) 0.09 (0.76) (0.43–5.46) 0.0 (0.81–6.33) 50.0 (0.03–1.87) 10.0 (0.26–16.61) 0.0 (0.25–3.12) 20.0
(1.15–8.04) (0.12–6.99) (0.31–20.48) (0.59–4.18) (0.50–10.65) NC 2.20 (0.77–6.29) 2.33 (0.81–6.66) NC
50.0 10.0 0.0 10.0 10.0 0.0 30.0 30.0 —
Nonattempter (n = 392) –0.02 –0.02 –0.01 –0.01 –0.01 –0.01 –0.02 –0.02 0.00 –0.01 0.01 0.00 0.00 13.9 56.9 12.2 1.4 16.4
(0.99) (1.00) (1.00) (1.00) (1.00) (1.00) (1.00) (0.99) (1.00) (1.00) (1.01) (1.00) (1.01)
21.7 3.3 1.5 10.2 12.5 5.9 19.9 19.4 —
OR (95% CI) 2.51 2.55 1.97 1.06 1.10 2.59 1.12 2.43 1.09 1.04 0.94 1.23 1.15
(1.07–5.86) (1.05–6.16) (0.86–4.56) (0.97–1.17) (0.98–1.24) (0.87–7.67) (1.02–1.23) (1.02–5.76) (0.39–3.00) (0.99–1.09) (0.81–1.09) (0.42–3.65) (0.44–3.02) NC 0.76 (0.22–2.66) 0.80 (0.10–6.47) NC 1.27 (0.26–6.11)
3.61 (1.02–12.78) 3.18 (0.37–27.14) NC 0.97 (0.12–7.86) 0.80 (0.10–6.53) NC 1.73 (0.44–6.85) 1.80 (0.45–7.14) —
Note: OR = odds ratio; CI = confidence interval; NC = not calculable. Significant odds ratios appear in boldface type.
young adulthood for female, but not male, participants. Given that a suicide attempt has almost always been shown to be an important risk factor for future suicidal behavior, this finding was unexpected and needs to be independently replicated. Given that the psychosocial risk factors in this study were chosen because they had been previously shown to predict a future suicide attempt during adolescence, it is interesting to examine those that continue to predict (which have already been listed in the Results section) and those that clearly did not predict. To wit: having a teenage mother, lower parental education, suicide attempt by a friend and certain functional impairments stemming from a physical disease during adolescence appear to be time-limited risk factors for adolescent suicidal behavior. Other psychosocial variables that did not attain the p < .05 level of statistical significance were in the predicted 432
direction and may not have attained statistical significance because of a lack of statistical power. These variables include high self-consciousness, low social self-competence, elevated daily hassles and major life events, hopelessness (as per single BDI item), and problems with appetite. Caution is needed with regard to drawing negative conclusions concerning these variables. With a larger sample size, these factors might have attained statistical significance. However, it seems fair to conclude that these variables are not among the strongest predictors of suicide attempt in young adults. In the same vein, we should be cautious in concluding that a variable predicts for one gender (because it is significant) and not for the other (because it is not significant). In all instances in which a variable is significant for only one gender, results were in the same direction for the other gender. Thus, this discrepancy could be an issue of statistical power. The variable J . A M . A C A D . C H I L D A D O L E S C . P S YC H I AT RY, 4 0 : 4 , A P R I L 2 0 0 1
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with the largest gender difference was social support from one’s family, which significantly predicted attempts for young women but was unrelated to suicidal behavior for young men. Of the adolescent psychiatric disorders, MDD was the only disorder that significantly predicted future suicide attempts. Among the other examined disorders, drug and alcohol use problems might have become significant with a larger sample. Limitations
Several limitations of the study should be noted. First, suicide attempts are a low base-rate phenomenon, and the number of participants who made an attempt in young adulthood was relatively small. Given the low frequency of suicide attempts in young adulthood, it is important not to overstate the clinical significance of gender differences. The low frequency of suicide attempts reduces statistical power to detect differences and increases the chance of type II errors. Thus, caution is needed in accepting the null hypothesis. Low sample sizes are almost always an issue in this area of research. Thus, the present results need to be replicated in independent, large samples. Second, although the sample was representative of the population from which it was selected and attrition was relatively low, participation at the T1 assessment was somewhat low (although consistent with other studies), and the sample had few members of racial/ethnic minorities. A third potential confound is the repeated assessments. An individual’s response may be affected in unknown ways by asking the same questions repeatedly. Finally, the fact that most of the suicide attempts and episodes of depression occurred before the diagnostic interview is a limitation. Thus, rather than representing a real decrease in the rate of depression, the apparent decrease in MDD rates at ages 19 to 20 shown in Figure 1 may reflect the fact that the interval between the T3 interview (age 24) and the immediately preceding assessment (T2) was longer (4–6 years) than the interval between the T2 assessment (conducted between ages 15 and 19) and the preceding assessment (T1). It stands to reason that the more time that has elapsed since the MDD episode, the greater the likelihood of forgetting. Perhaps a similar decrease in recall associated with retrospective reporting was not found for suicide attempts because they constitute specific and dramatic events that might be clearly remembered, even over longer intervals. These are methodological issues that should be addressed in future research. However, there J . A M . A C A D . C H I L D A D O L E S C . P S YC H I AT RY, 4 0 : 4 , A P R I L 2 0 0 1
is no reason to assume that any of the above-mentioned limitations are associated with gender, and, consequently, we do not believe that they vitiate our results. The present study also has positive features, including (1) a relatively large sample, which provided reasonable power to detect gender differences; (2) its longitudinal design of three repeated assessments over a 6- to 10-year period, which decreased the time frame for retrospective reporting biases; (3) the use of an interviewer-administered assessment of suicidal behavior and depression; and (4) the use of a randomly selected sample of community adolescents, which reduced biases associated with treatmentseeking and mental health treatment utilization. Clinical Implications
The fact that suicidal behavior during adolescence predicted suicide attempts in young adulthood for women has obvious clinical implications. A history of suicide attempt is relatively easy to probe for (e.g., Have you ever done anything that might have killed you?) and was associated with a three-fold increase in suicide attempts during young adulthood for women. It is similarly easy to probe for the presence of suicidal ideation during adolescence. Our results suggest that both adolescent suicidal ideation and suicide attempts are predictive of future attempts in young women. For young men, poor coping was the most salient predictor of future attempt. Poor coping was assessed with a small number of items categorized as either ineffective escapism (e.g., not doing something dangerous; staying in bed) or failure to engage in either solace seeking (e.g., spend time with friends) or cognitive self-control (e.g., when I am faced with a difficult problem, I try to approach its solution in a systematic way). Our findings suggest that etiological factors related to suicide attempts for men and women may differ. Such differences may need to be taken into account in clinical assessment and the design of interventions. Other measures that constitute risk factors but which may or may not be available to clinicians on the basis of their clinical assessment are a pessimistic and self-blaming thinking style and low social support from family and friends. It is not surprising that a history of adolescent MDD is the single most influential risk factor for men and women and should always be part of the assessment of suicidal risk. Perhaps the most important finding is that the relative degree of risk created by various factors appears to differ somewhat in young women and men. This may need to be included in screening and develop433
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ing interventions for those at elevated risk for a suicide attempt during young adulthood. REFERENCES Andrews JA, Lewinsohn PM, Hops H, Roberts RE (1993), Psychometric properties of scales for the measurement of psychosocial variables associated with depression in adolescence. Psychol Rep 73:1019–1046 Beck AT, Ward CH, Mendelson M, Mock J, Erbaugh J (1961), An inventory for measuring depression. Arch Gen Psychiatry 4:561–571 Brent DA, Perper JA, Moritz G et al. (1993), Psychiatric risk factors for adolescent suicide: a case-control study. J Am Acad Child Adolesc Psychiatry 32:521–529 Canetto SS (1998), The gender paradox in suicide. Suicide Life Threat Behav 28:1–23 Centers for Disease Control (2000), 1999 Youth Risk Behavior Surveillance: sadness and suicide ideation and attempts. MMWR Morb Mortal Wkly Rep 49(SS-05):1–96 Fenigstein A, Scheier MF, Buss AH (1975), Public and private self-consciousness: assessments and theory. J Consult Clin Psychol 43:522–527 Garrison CZ, Jackson KL, Addy CL, McKeown RE, Waller JL (1991), Suicidal behaviors in young adolescents. Am J Epidemiol 133:1005–1014 Garrison CZ, McKeown RE, Valois RF, Vincent ML (1993), Aggression, substance use, and suicidal behaviors in high school students. Am J Public Health 83:179–184 Harrington R, Bredenkamp D, Groothues C, Rutter M (1994), Adult outcomes of childhood and adolescent depression, III: links with suicidal behaviours. J Child Psychol Psychiatry 35:1309–1319 Hawton K (1992), Suicide and attempted suicide. In: Handbook of Affective Disorders, Paykel ES, ed. London: Guilford, pp 635–650 Hirschfeld RMA, Klerman GL, Chodoff P, Korchin S, Barrett J (1976), Dependency–self-esteem–clinical depression. J Am Acad Psychoanal 4:373–388 Holmes TH, Rahe RH (1967), The Social Readjustment Scale. J Psychosom Res 11:213–218 Keller MB, Lavori PW, Friedman B, Nielsen E, Endicott J, McDonald-Scott PA (1987), The Longitudinal Interval Follow-up Evaluation: a comprehensive method for assessing outcome in prospective longitudinal studies. Arch Gen Psychiatry 44:540–548 Kessler RC, McGonagle KA, Swartz M, Blazer DG, Nelson CB (1993), Sex and depression in the National Comorbidity Survey, I: lifetime prevalence, chronicity, and recurrence. J Affect Disord 29:85–96 Kessler RC, McRae JA Jr (1983), Trends in the relationship between sex and attempted suicide. J Health Soc Behav 24:98–110
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Kovacs M, Goldston D, Gatsonis C (1993), Suicidal behaviors and childhoodonset depressive disorders: a longitudinal investigation. J Am Acad Child Adolesc Psychiatry 32:8–20 Lewinsohn PM, Hops H, Roberts RE, Seeley JR, Andrews JA (1993), Adolescent psychopathology, I: prevalence and incidence of depression and other DSM-III-R disorders in high school students. J Abnorm Psychol 102:133–144 Lewinsohn PM, Mermelstein RM, Alexander C, MacPhillamy D (1985), The Unpleasant Events Schedule: a scale for the measurement of aversive events. J Clin Psychol 41:483–498 Lewinsohn PM, Rohde P, Seeley JR (1994), Psychosocial risk factors for future adolescent suicide attempts. J Consult Clin Psychol 62:297–305 Lewinsohn PM, Rohde P, Seeley JR (1996), Adolescent suicidal ideation and attempts: prevalence, risk factors and clinical implications. Clin Psychol Sci Pract 3:25–46 Marttunen MJ, Aro HM, Henriksson MM, Lonnqvist JK (1991), Mental disorders in adolescent suicide: DSM-III-R axes I and II diagnoses in suicides among 13- to 19-year-olds in Finland. Arch Gen Psychiatry 48:834–839 Meehan PJ, Lamb JA, Saltzman LE, O’Carroll PW (1992), Attempted suicide among young adults: progress towards a meaningful estimate of prevalence. Am J Psychiatry 149:41–44 Moscicki EK (1994), Gender differences in completed and attempted suicides. Ann Epidemiol 4:152–158 National Vital Statistics Report (1999), Table 8. Vol. 47, No. 19, page 27. http://www.cdc.gov/nchswww/data/nvs47_19.pdf Orvaschel H, Puig-Antich J, Chambers WJ, Tabrizi MA, Johnson R (1982), Retrospective assessment of prepubertal major depression with the Kiddie-SADS-E. J Am Acad Child Psychiatry 21:392–397 Petronis KR, Samuels JF, Moscicki EK, Anthony JC (1990), An epidemiologic investigation of potential risk factors for suicide attempts. Soc Psychiatry Psychiatr Epidemiol 25:193–199 Rosenberg ML, Smith JC, Davidson LE, Conn JM (1987), The emergence of youth suicide: an epidemiologic analysis and public health perspective. Ann Rev Public Health 8:417–440 Sandler IN, Block M (1979), Life stress and maladaption of children. Am J Community Psychol 7:425–439 Shaffer D, Hicks R (1992), Suicide and suicidal behaviors. In: Textbook of Adolescent Medicine, McAnarney ER, Kreipe RE, Orr DP, Comerci GD, eds. Philadelphia: Saunders, pp 979–986 Weissman MM (1974), The epidemiology of suicide attempts, 1960 to 1971. Arch Gen Psychiatry 30:737–746 Wexler L, Weissman MM, Kasl SV (1978), Suicide attempts 1970–1975: updating a United States study and comparisons with international trends. Br J Psychiatry 132:180–185
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ABSTRACT Objective: To examine associations of age, gender, and psychosocial factors during adolescence with risk of suicide attempt between ages 19 and 23 years. Method: Initial assessments were conducted with 1,709 adolescents (aged 14–18) in western Oregon between 1987 and 1989. One year later, 1,507 participants returned for a second assessment. A subset of participants (n = 941; 57.2% women) had a third diagnostic assessment after turning 24 (between 1993 and 1999). Information on suicidal behavior, psychosocial risk factors, and lifetime DSM-III-R psychiatric diagnosis was collected at each assessment. Results: The suicide attempt hazard rate for female adolescents was significantly higher than for male adolescents (Wilcoxon χ21[n = 941] = 12.69, p < .001). By age 19, the attempt hazard rate for female adolescents dropped to a level comparable with that of male adolescents. Disappearance of the gender difference for suicide attempts by young adulthood was not paralleled by a decrease in the gender difference for major depression. Adolescent suicidal behavior predicted suicide attempt during young adulthood for female, but not male, participants. Adolescent psychosocial risk factors for suicide attempt during young adulthood were identified separately for girls and boys. Conclusions: Unlike depression, the elevated incidence rate of suicide attempts by adolescent girls is not maintained into young adulthood. Screening and prevention implications are discussed. J. Am. Acad. Child Adolesc. Psychiatry, 2001, 40(4):427–434. Key Words: suicide attempt, gender, age, major depression.
Adolescent suicide attempts are an important public health problem. Rates of both suicide attempts and completions by adolescents have increased since the 1960s (Centers for Disease Control, 2000; Rosenberg et al., 1987; Wexler et al., 1978), and suicide is currently the third leading cause of mortality among 15- to 24-year-olds (National Vital Statistics Report, 1999). Recent epidemiological studies suggest that the lifetime rate of suicide attempts among high school students ranges from 3% to 15% (Centers for Disease Control, 2000; Lewinsohn et al., 1994; Shaffer and Hicks, 1992). Although the majority of these attempts are of low medical lethality (Lewinsohn et al., 1996), having made a past suicide attempt is the strongest predictor of both future suicide attempts and completions (Hawton, 1992; Shaffer and Hicks, 1992). Accepted November 7, 2000. From the Oregon Research Institute, Eugene. This research was supported in part by NIMH awards MH40501, MH50522, and MH52858. Reprint requests to Dr. Lewinsohn, Oregon Research Institute, 1715 Franklin Blvd., Eugene, OR 97403-1983; e-mail: [email protected]. 0890-8567/01/4004-0427䉷2001 by the American Academy of Child and Adolescent Psychiatry.
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Marked developmental trends exist in the frequency of suicide attempts. Attempts before adolescence are extremely rare, but a sharp increase occurs during early adolescence (13–18 years of age), followed by an apparent decrease as adolescents enter early adulthood (Lewinsohn et al., 1996; see also Garrison et al., 1993; Hawton, 1992; Shaffer and Hicks, 1992). Nearly all of these investigations, however, were based on cross-sectional and lifetime retrospective reports. In this article, we report the results of a prospective study of community young adults who were originally assessed during high school (Lewinsohn et al., 1993). The first goal of the present study was to describe the pattern of suicide attempts from childhood through 23 years of age separately for male and female participants. To our knowledge, a fine-grained analysis of the relationships between age, gender, and suicide attempts between adolescence and young adulthood has yet to be conducted. Gender differences in suicidal behavior are known to exist. Although rates of completed suicide are higher for men in both adolescence and adulthood (Meehan et al., 1992; Shaffer and Hicks, 1992) rates of suicide attempt are two to three times greater for female adolescents 427
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compared with male adolescents (Lewinsohn et al., 1996; see also Hawton, 1992; Kessler and McRae, 1983; Weissman, 1974; Wexler et al., 1978). Several explanations for this “gender paradox” have been proposed (Canetto, 1998; Moscicki, 1994), including gender differences in the lethality of suicide attempt methods, accuracy and honesty in reporting of past suicidal behavior, frequency of depression versus substance use disorders, and socialization regarding culturally acceptable forms of self-destructive behaviors. No single explanation appears to adequately account for these differences. One possible explanation for the elevated rate of suicide attempts among young women is their elevated rate of depression (Lewinsohn et al., 1993; see also Kessler et al., 1993). Suicidal behavior (i.e., ideation and attempts) is an important symptom of major depressive disorder (MDD) as per the DSM-IV, and research has repeatedly shown associations between depression and suicidal behavior in both adolescents and adults (Brent et al., 1993; Garrison et al., 1991; Harrington et al., 1994; Kovacs et al., 1993; Marttunen et al., 1991; Petronis et al., 1990). The second goal of this study was to superimpose associations between age, gender, and suicide attempt onto comparable associations between age, gender, and MDD. To what extent does the gender ratio for suicide attempts parallel the gender ratio for MDD from adolescence to young adulthood? This study also examines the extent to which suicidal behavior and other psychosocial risk factors that predict adolescent suicide attempts act as risk factors for suicide attempts in young adulthood. We previously found (Lewinsohn et al., 1994) that prior suicide attempts and suicidal ideation, depression, negative cognitions, low self-esteem, low social support from family, and difficulty climbing stairs as a result of physical illness were among the strongest predictors of future suicide attempts 1 year later in adolescence. In the present study, we examined whether these risk factors are influential over a much longer time interval. The present study is one in a series of reports from the Oregon Adolescent Depression Project (OADP), which is based on a large, randomly selected cohort of high school students who were assessed at two points over a period of 1 year (T1 and T2) by means of rigorous diagnostic criteria and structured diagnostic interviews. Recently, a large subset of OADP participants completed a third (T3) interview after their 24th birthday. Data regarding suicide attempts were obtained at all diagnostic assessments. 428
METHOD Participants OADP participants were randomly selected from nine senior high schools in western Oregon. A total of 1,709 adolescents (ages 14–18) completed the initial (T1) assessments (interview and questionnaires) between 1987 and 1989, with an overall participation rate of 61%. At the second assessment (T2), 1,507 participants (88%) returned for a readministration of the interview and questionnaire (mean T1–T2 interval = 13.8 months, SD = 2.3). Differences between the sample and the larger population from which it was selected, and between participants and those who declined to participate or dropped out of the study, were small (additional details regarding the T1 and T2 assessments are provided by Lewinsohn et al., 1993). After individuals reached their 24th birthday (between 1993 and 1999), all participants with a history of MDD at T2 (n = 360), those with a history of other psychopathology at T2 (n = 284), and a subset of participants with no history of mental disorder at T2 (n = 457) were invited to participate in a T3 interview. Sampling of the no-disorder comparison group was proportional to age, and gender within age; all participants with nonwhite ethnicity were invited to participate in the T3 assessments. Of the 1,101 individuals selected for T3 interview, 941 young adults (85%) participated (57% female; average T3 age = 24.2 years, SD = 0.6; 89% white; 34% married; 97% graduated from high school; 31% received a bachelor’s degree or higher). Women were more likely than men to complete the T3 assessments (89% versus 81%; χ21[n = 1,101] = 13.55, p < .001). Differences in T3 participation as a function of other demographics or T2 diagnostic status were nonsignificant. Those with a history of suicide attempt at T2 were more likely than nonattempters to complete the T3 assessments (93% versus 84%; χ21[n = 1,101] = 5.02, p < .05). Diagnostic Interviews Participants were interviewed at T1 with a version of the Schedule for Affective Disorders and Schizophrenia for School-Age Children (K-SADS), which combined features of the Epidemiologic version (Orvaschel et al., 1982) and the Present Episode version and included additional items to derive DSM-III-R diagnoses. At T2 and T3, participants were interviewed with the Longitudinal Interval Followup Evaluation (LIFE) (Keller et al., 1987), in combination with the K-SADS. (The LIFE procedure was used to track the course of preexisting disorders and to probe for the development of new disorders; when they occurred, symptoms and characteristics of new disorders in the follow-up period were assessed with relevant sections of the K-SADS.) This combined procedure elicited detailed information about the course of psychiatric symptoms and disorders, including suicidal behavior since the previous interview. T3 diagnoses were made with the LIFE/K-SADS methodology, revised for DSM-IV criteria. Diagnostic interviewers were carefully selected and trained; most interviewers held advanced degrees in clinical psychology, counseling psychology, or social work, and all of them completed an experiential course in diagnostic interviewing. After interviews were completed, diagnostic packets were carefully reviewed by supervisors for completion and accuracy. On the basis of a randomly selected subsample of participants at T1 and T2 (n = 233), interrater reliability for lifetime diagnoses were moderate to excellent: MDD (κ = 0.86), dysthymia (κ = 0.58), bipolar disorder (κ = 0.49), anxiety disorder (κ = 0.76), disruptive behavior disorders (κ = 0.83), alcohol abuse/dependence (κ = 0.84), and drug abuse/dependence (κ = 0.84). During the T2–T3 period, interrater reliability for the diagnosis of MDD in a review of
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178 randomly selected interviews was excellent (κ = 0.87). In the T3 sample (in which participants with past psychopathology were overrepresented), 455 (48.5%) had no history of MDD, 283 (30.1%) had one lifetime episode of MDD, and 202 (21.5%) had multiple episodes of MDD. Assessment of Suicidal Behavior Information on suicidal behavior was collected with similar probes at each of the three interviews. The operational definition of suicidal ideation was based on endorsement of at least one of three questions from the K-SADS (thoughts of death or dying, wishing to be dead, or thinking about hurting or killing oneself ). The operational definition of a suicide attempt was a positive response to the question, “Have you ever (or “since the last interview”) tried to kill yourself or done anything that could have killed you,” followed by additional probes to eliminate purely thrill-seeking behaviors and to determine the person’s age at the time of the attempt. Interrater reliability for a suicide attempt was excellent at T1 (κ = 0.95, n = 213); interrater reliability was not available at T2 and T3 because of the low number of suicide attempts in the reliability sample. Of the T3 participants, 816 (86.7%) had no history of suicide attempts, 72 (7.7%) reported one attempt, and 52 (5.5%) reported multiple attempts. Psychosocial Measures An extensive battery of psychosocial measures was administered to all participants at T1. All measures had been previously shown to posses very good psychometric properties (Andrews et al., 1993; Lewinsohn et al., 1993). Variables were standardized and scored such that higher values reflected more problematic functioning. In a previous report (Lewinsohn et al., 1994), we identified a set of 18 psychosocial variables that were significant risk factors for making a suicide attempt during adolescence (i.e., from T1 to T2), which were examined in the present study as predictors of suicide attempt from T2 to T3. Negative cognitions were assessed with 27 items that concern selfreinforcement, likelihood of future positive events, dysfunctional attitudes, and perceived control over one’s life (α = .81). Attributional style was assessed with the 48-item Kastan Attributional Style Questionnaire for Children (α = .63) (N. Kaslow et al., unpublished, 1978). Self-esteem was assessed with 9 items regarding physical appearance and general self-esteem (α = .81). Excessive emotional reliance was assessed with 10 items that examine the extent to which individuals desire excessive support and approval from others and are interpersonally sensitive (α = .83) (Hirschfeld et al., 1976). Self-consciousness was assessed with 9 items from the Self-Consciousness Scale (α = .74) (Fenigstein et al., 1975). Social self-competence was assessed with 12 items (α = .85). Coping skills were assessed with 17 items (α = .76). Social support: Friends was assessed with 13 items (α = .81). Social support: Family was assessed with 22 items (α = .86). Daily hassles were assessed with 20 items from the Unpleasant Events Schedule (α = .79) (Lewinsohn et al., 1985). Major life events were assessed with 14 events from the Schedule of Recent Experience (Holmes and Rahe, 1967) and the Life Events Schedule (Sandler and Block, 1979), rated for occurrence to self or significant others in the past year (α = .78). The following single item measures were also included: teenage mother (i.e., mother was less than 20 years of age at the time of the participant’s birth); parental education (i.e., bachelor’s degree obtained by either parent); Beck Depression Inventory Hopelessness item (Beck et al., 1961); suicide attempt by friend in the past year; problems with appetite (rated on a four-point scale); difficulties with climbing stairs and difficulties with activities in the past year because of illness or injury.
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Psychopathology Before Age 19 On the basis of the K-SADS interviews conducted at T1, T2, and T3, incidence of the following psychiatric disorders occurring before 19 years of age were included as predictor variables: MDD (n = 328), dysthymia (n = 43), bipolar disorder (n = 18), anxiety disorders (n = 160), conduct/oppositional disorders (n = 77), attention-deficit/hyperactivity disorder (n = 34), alcohol abuse/dependence (n = 156), drug abuse/dependence (n = 151), and eating disorders (n = 21). Data Analysis Life table survival methods were used to calculate annual hazard rates for suicide attempt and for MDD; calculations were based on 2year intervals from birth through age 24. Analyses were conducted with two samples: (1) all T1 participants, with those who did not participate at T2 or T3 and who did not experience an event (i.e., suicide attempt or major depression episode) being censored at their last observation point; and (2) only T3 participants. Given the comparability of results, data from the T3 participants are presented. Contingency tables and logistic regression analysis were used to test gender differences in period prevalence rates and to test prospective associations between suicidal behavior, psychosocial risk factors, and psychopathology. Alpha was set to p < .05, two-tailed, for χ2 tests and odds ratios (ORs). Because participants without a history of psychopathology at T2 were undersampled at T3, both observed and weighted rates are reported. RESULTS Suicide Attempt Rates From Childhood to Young Adulthood
Annual hazard rates in 2-year intervals for first suicide attempts for female and male participants from childhood to young adulthood are shown in the upper portion of Figure 1. Each interval shown in the figure contains the annual hazard rates for that year of age and the preceding year (e.g., the interval labeled “14” consists of the average hazard rates for ages 13 and 14). The survival curves for the two genders were significantly different (Wilcoxon χ21[n = 941] = 12.69, p < .001). As can be seen, beginning at age 13, the suicide attempt annual hazard rates increase rapidly for girls, who are at elevated risk between the ages of 15 and 18. The annual hazard rate for women decreases during the period of 19 to 23 years of age. Rates of first attempt for boys reach their highest levels at age 15 and are maintained until age 20. By age 19, the hazard rates for both genders are quite similar. For comparison purposes, annual hazard rates for the first incidence of MDD as a function of gender are shown in the lower portion of the figure. Significant differences were present in MDD hazard rate curves for male and female participants (Wilcoxon χ21[n = 941] = 61.15, p < .001). MDD rates for both genders increased markedly by age 15, with the hazard rate for girls approximately twice that of boys. In contrast to the suicide attempt haz429
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Fig. 1 Annual hazard rates for first episode of suicide attempt (SA) and major depressive disorder (MDD) as a function of gender.
ard rates, however, the hazard rates for MDD do not significantly decrease in young adulthood for either gender. Period prevalence rates of suicide attempt were examined in three developmental periods (1) childhood, defined as ages 5 to 11, (2) adolescence, defined as ages 12 to 18, and (3) young adulthood, defined as ages 19 to 23. The percentage of female and male participants who had made a suicide attempt (first or recurrent) in each of the three time periods was contrasted; results are shown in Table 1. Even though five of the six children who made an attempt were girls, this difference was not statistically significant. In adolescence, female participants had a significantly higher rate of suicide attempts compared with male participants. The gender difference did not attain statistical significance during young adulthood. Also shown in Table 1 are the percentages of male and female participants who experienced an episode of MDD (first or recurrent) during the three developmental periods. Significant gender differences in MDD occurrence were present for all three periods, with female participants having consistently higher rates than male participants.
TABLE 1 Gender Differences in Suicide Attempt and Major Depressive Disorder During Childhood, Adolescence, and Young Adulthood Outcome/Time Period Suicide attempt (%) 5–11 years of age Observeda Weightedb 12–18 years of age Observed Weighted 19–23 years of age Observed Weighted Occurrence of MDD (%) 5–11 years of age Observed Weighted 12–18 years of age Observed Weighted 19–23 years of age Observed Weighted
Female Sample
Male Sample
χ2
0.9 0.8
0.2 0.2
1.88 3.12
12.8 9.9
6.0 4.2
3.7 3.2
2.5 1.8
6.9 5.1
1.7 1.2
15.22*** 17.97***
4.16 (1.83–9.43) 4.61 (2.04–10.41)
40.1 30.2
21.1 14.8
39.00*** 44.95***
2.49 (1.86–3.35) 2.49 (1.89–3.29)
36.5 33.8
19.7 16.9
32.64*** 50.03***
2.36 (1.74–3.19) 2.51 (1.93–3.27)
12.70*** 16.68*** 1.12 2.44
OR (95% CI)
3.78 5.03
(0.43–32.26) (0.60–41.98)
2.31 (1.43–3.75) 2.53 (1.58–4.04) 1.51 (0.70–3.26) 1.77 (0.86–3.67)
Note: OR = odds ratio; CI = confidence interval; MDD = major depressive disorder. a df = 1, N = 941. b df = 1, N = 1,320. *** p < .001.
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Association Between Adolescent Suicidal Behavior and Suicide Attempt During Young Adulthood
To examine the association between suicidal behavior during childhood/adolescence and suicide attempt during young adulthood, and to test for moderating effects of gender, a hierarchical logistic regression analysis was conducted to predict suicide attempt in young adulthood. The first block included history of suicidal behavior (either suicide ideation or attempt) before age 19 and gender. The second block included the interaction term between suicidal behavior and gender. A significant main effect was obtained for adolescent suicidal behavior (likelihood ratio: χ21[n = 941] = 14.40, p < .001; OR = 4.26, 95% confidence interval [CI] = 1.98–9.11), but not for gender. However, the two-way interaction between gender and adolescent suicide behavior significantly improved the model fit (likelihood ratio: χ21[n = 941] = 3.89, p < .05). To interpret the significant interaction, the association between adolescent suicide behavior and suicide attempt during young adulthood was examined separately by gender. Compared with female participants who did not attempt suicide in young adulthood (n = 519), young adult female attempters (n = 20) had elevated rates of suicide ideation (80% versus 31%; OR = 8.81, 95% CI = 2.90–26.78) and suicide attempt (35% versus 13%; OR = 3.63, 95% CI = 1.40–9.43) during adolescence. In contrast, young adult male attempters (n = 10) did not differ significantly from male nonattempters (n = 392) with respect to suicide ideation (30% versus 20%, OR = 1.67, 95% CI = 0.42–6.61) and suicide attempt (0% versus 6%; OR = not calculable) during adolescence. Thus, continuity in suicidal behavior was obtained only for female participants. Prediction of Suicide Attempt in Young Adulthood
In a previous report (Lewinsohn et al., 1994), we identified a set of psychosocial risk factors for making a suicide attempt during adolescence (i.e., between T1 and T2). To examine the extent to which these risk factors predicted a suicide attempt in the 19–23 year period, hierarchical logistic regression analyses were conducted. In addition to the psychosocial risk factors, history of psychopathology before age 19 was included in the model. Given the significant gender difference obtained for the association between adolescent suicidal behavior and suicide attempt during young adulthood, the models were tested separately by gender. Because the participants varied in age (range 14–18 years) at the time of the T1 J . A M . A C A D . C H I L D A D O L E S C . P S YC H I AT RY, 4 0 : 4 , A P R I L 2 0 0 1
assessment, age was included as a covariate in the analyses. The mean score or proportion for attempters and nonattempters, along with the ORs for making an attempt in young adulthood, are presented in Table 2. As can be seen, the significant predictors for female participants include negative cognitions, low self-esteem, excessive emotional reliance on others, poor coping skills, low social support from family, and a history of MDD before age 19. For male participants, the significant predictors include negative cognitions, depressotypic attributional style, poor coping skills, low social support from friends, and a history of MDD before age 19. Summary logistic regression models were tested on the set of significant predictors for each gender with the likelihood ratio backward deselection procedure. Because suicide ideation and attempt before age 19 were significantly associated with a suicide attempt in young adulthood for female participants, they were also included in the model. Of the eight significant predictors of suicide attempts by young women, only previous suicide ideation was retained in the model (likelihood ratio: χ21[n = 539] = 14.19, p < .001). For male participants, of the five significant predictors, only poor coping skills was retained in the model (likelihood ratio: χ21[n = 402]= 5.64, p < .05). DISCUSSION
Several somewhat unexpected findings are noteworthy. First, without disaggregating results for male and female participants, we would have erroneously concluded that the suicide attempt rate decreases from adolescence to young adulthood. In fact, a significant drop in hazard rate is evident only for young women. Future research needs to examine whether annual hazard rates remain at this low level as the participants move further into adulthood. Disappearance of the gender difference for suicide attempts by young adulthood is not accounted for by a parallel decrease in the gender difference for MDD. Female gender is significantly associated with MDD in each of the three developmental periods, with an OR greater than 2.0 in each time period. Research to identify factors that account for the high rate of depression in girls beginning at a very early age deserves a high priority. Similarly, research to explain the high rate of suicide attempt in female adolescents and the decline in the suicide attempt rate in young women is needed. Suicidal behavior (ideation or attempt) during childhood and adolescence predicted a suicide attempt during 431
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TABLE 2 Psychosocial and Psychopathological Predictors of Suicide Attempt in Young Adulthood Female Sample (n = 539) Variable Psychosocial Negative cognitions: M (SD) Attributional style: M (SD) Self-esteem: M (SD) Emotional reliance: M (SD) Self-consciousness: M (SD) Social self-competence: M (SD) Coping skills: M (SD) Friend support: M (SD) Family support: M (SD) Daily hassles: M (SD) Major events: M (SD) BDI Hopelessness: M (SD) Problems with appetite: M (SD) Teenage mother (%) Parental education (%) Attempt by friend (%) Difficulty climbing stairs (%) Difficulty with activities (%) Psychopathology Major depression (%) Dysthymia (%) Bipolar disorder (%) Anxiety disorder (%) Conduct/oppositional (%) Attention deficit (%) Alcohol abuse/dependence (%) Drug abuse/dependence (%) Eating disorder (%)
Attempter (n = 20) 0.55 0.28 0.54 0.44 0.27 0.40 0.50 0.37 0.67 0.07 0.31 0.27 0.34 15.0 75.0 5.0 5.0 15.0 70.0 5.0 5.0 30.0 10.0 0.0 25.0 25.0 0.0
(0.92) (0.77) (0.97) (1.01) (1.05) (1.32) (1.00) (1.55) (0.88) (1.23) (0.98) (1.17) (1.19)
Nonattempter (n = 519) –0.02 –0.01 –0.02 –0.02 –0.01 –0.02 –0.02 –0.01 –0.03 0.00 –0.01 –0.01 –0.01 11.5 56.6 17.7 2.8 18.5
(1.00) (1.01) (0.98) (1.00) (1.00) (0.98) (1.00) (0.97) (1.00) (0.99) (1.00) (0.99) (0.99)
43.2 5.4 2.1 21.8 4.8 2.1 13.5 12.9 3.7
OR (95% CI) 2.12 1.40 2.11 1.07 1.06 2.13 1.07 1.77 2.69 1.01 1.05 1.45 1.52 1.53 2.26 0.25 2.06 0.89 3.04 0.90 2.50 1.57 2.31
Male Sample (n = 402) Attempter (n = 10)
(1.18–3.81) 0.68 (1.17) (0.85–2.31) 0.65 (0.86) (1.16–3.85) 0.50 (0.87) (1.01–1.15) 0.41 (1.13) (0.97–1.16) 0.55 (0.91) (0.95–4.77) 0.52 (0.99) (1.01–1.13) 0.74 (0.88) (0.92–3.40) 0.64 (1.06) (1.41–5.13) 0.05 (1.08) (0.97–1.04) 0.50 (0.81) (0.98–1.12) –0.27 (0.76) (0.78–2.68) 0.14 (0.93) (0.88–2.64) 0.09 (0.76) (0.43–5.46) 0.0 (0.81–6.33) 50.0 (0.03–1.87) 10.0 (0.26–16.61) 0.0 (0.25–3.12) 20.0
(1.15–8.04) (0.12–6.99) (0.31–20.48) (0.59–4.18) (0.50–10.65) NC 2.20 (0.77–6.29) 2.33 (0.81–6.66) NC
50.0 10.0 0.0 10.0 10.0 0.0 30.0 30.0 —
Nonattempter (n = 392) –0.02 –0.02 –0.01 –0.01 –0.01 –0.01 –0.02 –0.02 0.00 –0.01 0.01 0.00 0.00 13.9 56.9 12.2 1.4 16.4
(0.99) (1.00) (1.00) (1.00) (1.00) (1.00) (1.00) (0.99) (1.00) (1.00) (1.01) (1.00) (1.01)
21.7 3.3 1.5 10.2 12.5 5.9 19.9 19.4 —
OR (95% CI) 2.51 2.55 1.97 1.06 1.10 2.59 1.12 2.43 1.09 1.04 0.94 1.23 1.15
(1.07–5.86) (1.05–6.16) (0.86–4.56) (0.97–1.17) (0.98–1.24) (0.87–7.67) (1.02–1.23) (1.02–5.76) (0.39–3.00) (0.99–1.09) (0.81–1.09) (0.42–3.65) (0.44–3.02) NC 0.76 (0.22–2.66) 0.80 (0.10–6.47) NC 1.27 (0.26–6.11)
3.61 (1.02–12.78) 3.18 (0.37–27.14) NC 0.97 (0.12–7.86) 0.80 (0.10–6.53) NC 1.73 (0.44–6.85) 1.80 (0.45–7.14) —
Note: OR = odds ratio; CI = confidence interval; NC = not calculable. Significant odds ratios appear in boldface type.
young adulthood for female, but not male, participants. Given that a suicide attempt has almost always been shown to be an important risk factor for future suicidal behavior, this finding was unexpected and needs to be independently replicated. Given that the psychosocial risk factors in this study were chosen because they had been previously shown to predict a future suicide attempt during adolescence, it is interesting to examine those that continue to predict (which have already been listed in the Results section) and those that clearly did not predict. To wit: having a teenage mother, lower parental education, suicide attempt by a friend and certain functional impairments stemming from a physical disease during adolescence appear to be time-limited risk factors for adolescent suicidal behavior. Other psychosocial variables that did not attain the p < .05 level of statistical significance were in the predicted 432
direction and may not have attained statistical significance because of a lack of statistical power. These variables include high self-consciousness, low social self-competence, elevated daily hassles and major life events, hopelessness (as per single BDI item), and problems with appetite. Caution is needed with regard to drawing negative conclusions concerning these variables. With a larger sample size, these factors might have attained statistical significance. However, it seems fair to conclude that these variables are not among the strongest predictors of suicide attempt in young adults. In the same vein, we should be cautious in concluding that a variable predicts for one gender (because it is significant) and not for the other (because it is not significant). In all instances in which a variable is significant for only one gender, results were in the same direction for the other gender. Thus, this discrepancy could be an issue of statistical power. The variable J . A M . A C A D . C H I L D A D O L E S C . P S YC H I AT RY, 4 0 : 4 , A P R I L 2 0 0 1
GENDER AND SUICIDE ATTEMPTS
with the largest gender difference was social support from one’s family, which significantly predicted attempts for young women but was unrelated to suicidal behavior for young men. Of the adolescent psychiatric disorders, MDD was the only disorder that significantly predicted future suicide attempts. Among the other examined disorders, drug and alcohol use problems might have become significant with a larger sample. Limitations
Several limitations of the study should be noted. First, suicide attempts are a low base-rate phenomenon, and the number of participants who made an attempt in young adulthood was relatively small. Given the low frequency of suicide attempts in young adulthood, it is important not to overstate the clinical significance of gender differences. The low frequency of suicide attempts reduces statistical power to detect differences and increases the chance of type II errors. Thus, caution is needed in accepting the null hypothesis. Low sample sizes are almost always an issue in this area of research. Thus, the present results need to be replicated in independent, large samples. Second, although the sample was representative of the population from which it was selected and attrition was relatively low, participation at the T1 assessment was somewhat low (although consistent with other studies), and the sample had few members of racial/ethnic minorities. A third potential confound is the repeated assessments. An individual’s response may be affected in unknown ways by asking the same questions repeatedly. Finally, the fact that most of the suicide attempts and episodes of depression occurred before the diagnostic interview is a limitation. Thus, rather than representing a real decrease in the rate of depression, the apparent decrease in MDD rates at ages 19 to 20 shown in Figure 1 may reflect the fact that the interval between the T3 interview (age 24) and the immediately preceding assessment (T2) was longer (4–6 years) than the interval between the T2 assessment (conducted between ages 15 and 19) and the preceding assessment (T1). It stands to reason that the more time that has elapsed since the MDD episode, the greater the likelihood of forgetting. Perhaps a similar decrease in recall associated with retrospective reporting was not found for suicide attempts because they constitute specific and dramatic events that might be clearly remembered, even over longer intervals. These are methodological issues that should be addressed in future research. However, there J . A M . A C A D . C H I L D A D O L E S C . P S YC H I AT RY, 4 0 : 4 , A P R I L 2 0 0 1
is no reason to assume that any of the above-mentioned limitations are associated with gender, and, consequently, we do not believe that they vitiate our results. The present study also has positive features, including (1) a relatively large sample, which provided reasonable power to detect gender differences; (2) its longitudinal design of three repeated assessments over a 6- to 10-year period, which decreased the time frame for retrospective reporting biases; (3) the use of an interviewer-administered assessment of suicidal behavior and depression; and (4) the use of a randomly selected sample of community adolescents, which reduced biases associated with treatmentseeking and mental health treatment utilization. Clinical Implications
The fact that suicidal behavior during adolescence predicted suicide attempts in young adulthood for women has obvious clinical implications. A history of suicide attempt is relatively easy to probe for (e.g., Have you ever done anything that might have killed you?) and was associated with a three-fold increase in suicide attempts during young adulthood for women. It is similarly easy to probe for the presence of suicidal ideation during adolescence. Our results suggest that both adolescent suicidal ideation and suicide attempts are predictive of future attempts in young women. For young men, poor coping was the most salient predictor of future attempt. Poor coping was assessed with a small number of items categorized as either ineffective escapism (e.g., not doing something dangerous; staying in bed) or failure to engage in either solace seeking (e.g., spend time with friends) or cognitive self-control (e.g., when I am faced with a difficult problem, I try to approach its solution in a systematic way). Our findings suggest that etiological factors related to suicide attempts for men and women may differ. Such differences may need to be taken into account in clinical assessment and the design of interventions. Other measures that constitute risk factors but which may or may not be available to clinicians on the basis of their clinical assessment are a pessimistic and self-blaming thinking style and low social support from family and friends. It is not surprising that a history of adolescent MDD is the single most influential risk factor for men and women and should always be part of the assessment of suicidal risk. Perhaps the most important finding is that the relative degree of risk created by various factors appears to differ somewhat in young women and men. This may need to be included in screening and develop433
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