Associations of substance use patterns with attempted suicide among persons who inject drugs: Can distinct use patterns play a role?

• Associations of drug use patterns with suicide attempt (SA) among PWID were studied.
• Chronic and occasional use of stimulants was positively associated with SA.
• Chronic use of sedative-hypnotics was positively associated with SA.
• No association was found between SA and use of opioids, alcohol and cannabis.

BackgroundWhile the elevated risk of suicide attempt among persons who inject drugs (PWID) is well documented, whether use of different substances is associated with varying degrees of risk remains unclear. We sought to examine the associations between substance use patterns and attempted suicide in a prospective cohort of PWID in Montreal, Canada.MethodsBetween 2004 and 2011, participants completed an interviewer-administered questionnaire eliciting information on socio-demographics, substance use patterns, related behaviors, and mental health markers. Generalized estimating equations were used to model the relationship between self-reported use of six common substances (cocaine, amphetamine, opioids, sedative-hypnotics, cannabis and alcohol), associated patterns of use (chronic, occasional and none), and a recent (past six-month) suicide attempt.ResultsAt baseline, of 1240 participants (median age: 39.1, 83.7% male), 71 (5.7%) reported a recent suicide attempt. Among 5621 observations collected during follow-up, 221 attempts were reported by 143 (11.5%) participants. In multivariate analyses adjusting for socio-demographics and psychosocial stressors, among primary drugs of abuse, chronic [adjusted odds ratio (AOR): 1.97] and occasional (AOR: 1.92) cocaine use, and chronic amphetamine use (AOR: 1.96) were independently associated with attempted suicide. Among co-used substances, chronic sedative-hypnotic use was independently associated with an attempt (AOR: 2.29). No statistically significant association was found for the remaining substances.ConclusionAmong PWID at high risk of attempted suicide, stimulant users appear to constitute a particularly vulnerable sub-group. While the mechanisms underlying these associations remain to be elucidated, findings suggest that stimulant-using PWID should constitute a prime focus of suicide prevention efforts.