摘要：Objectives. We examined the longitudinal associations between different types and severities of childhood trauma and suicide attempts among illicit drug users. Methods. Data came from 2 prospective cohort studies of illicit drug users in Vancouver, Canada, in 2005 to 2010. We used recurrent event proportional means models to estimate adjusted and weighted associations between types and severities of childhood maltreatment and suicide attempts. Results. Of 1634 participants, 411 (25.2%) reported a history of suicidal behavior at baseline. Over 5 years, 80 (4.9%) participants reported 97 suicide attempts, a rate of 2.6 per 100 person-years. Severe to extreme levels of sexual abuse (adjusted hazard ratio [AHR] = 2.5; 95% confidence interval [CI] = 1.4, 4.4), physical abuse (AHR = 2.0; 95% CI = 1.1, 3.8), and emotional abuse (AHR = 3.5; 95% CI = 1.4, 8.7) predicted suicide attempts. Severe forms of physical and emotional neglect were not significantly associated with an increased risk of suicidal behavior. Conclusions. Severe sexual, physical, and emotional childhood abuse confer substantial risk of repeated suicidal behavior in adulthood. Illicit drug users require intensive secondary suicide prevention efforts, particularly among those with a history of childhood trauma. The global burden of suicide is considerable and is the tenth leading cause of death worldwide, with annual mortality estimated at 14.5 deaths per 100 000. 1 Suicide is a major and preventable public health problem among young people aged 15 to 24 years in Canada (second leading cause of death 2 ) and the United States (third leading cause of death 3 ). Each year, approximately 1 million adults in the United States attempt suicide, resulting in 35 000 deaths and more than 320 000 emergency department visits. 4 The societal, financial, and public health burdens associated with suicide are therefore substantial. The epidemiology of suicide is multifactorial and complex. 1 The 2012 National Strategy for Suicide Prevention identifies several groups at particularly high risk of suicide in the United States, including individuals with a past history of suicidal behavior, members of the armed forces and veterans, American Indians/Alaska Natives, men in midlife, and individuals in justice and child welfare settings. 5 Of public health concern in Canada, suicide rates among Aboriginal Peoples are 2 to 3 times that observed in the nonaboriginal population. 6,7 A large body of literature has also demonstrated high rates of suicidal behavior among lesbian, gay, bisexual, and transgender populations. 8–10 People who use illicit drugs are particularly vulnerable to suicidal ideation and behavior, and suicide is a leading cause of death in drug-using populations. 11,12 Furthermore, the relationship between substance abuse and increased suicide risk has been well established. 13,14 A growing body of research has examined various correlates of suicide attempts among drug users. In treatment-seeking samples of drug and alcohol abusers, major depressive disorder and other psychiatric conditions (e.g., borderline personality disorder, anxiety, agoraphobia) have been associated with a history of suicide attempts. 15–20 Furthermore, markers of social disadvantage and marginalization, such as unemployment and homelessness, are associated with a heightened risk of suicide and are common among drug users. 11 Specific typologies of drug use have also been linked to a greater likelihood of attempting suicide, including longer durations of substance use, 18,21 polysubstance use, 20,22 and injection methamphetamine use. 23 In recent years, childhood maltreatment has emerged as a consistent correlate of suicidal ideation and behavior among drug users. 19,24,25 These studies provide preliminary evidence that childhood abuse and neglect are important determinants of suicide in drug-using populations. However, it is unclear whether certain types of childhood maltreatment are more strongly associated with suicidal behavior than others. The majority of studies to date have examined suicide and early traumatic experiences among clinical samples, which may be subject to selection bias if being in treatment is a common effect of both exposure (i.e., childhood maltreatment) and other, unmeasured factors that may cause suicidal behavior (e.g., genetic or familial susceptibility to psychiatric disorders such as depression). To our knowledge no studies have prospectively examined suicidal behavior in a community-recruited cohort of drug users. Drug-using cohorts are particularly well suited to examining the relationship between childhood maltreatment and recurrent suicidal behavior because of their high rates of suicide. We used recurrent event survival models to determine the longitudinal associations between exposure to different types and severities of childhood trauma and suicide attempts, measured prospectively in a cohort of drug users in Vancouver, British Columbia.
