Injection methamphetamine use is associated with an increased risk of attempted suicide: A prospective cohort study

Abstract

Background Methamphetamine (MA) use is a growing public health concern in many settings around the world. While some physical and mental health effects associated with injection MA use have been well described, little is known about the relationship between injecting MA and suicidal behavior. We sought to determine whether MA injection was associated with an increased risk of attempting suicide among a prospective cohort of injection drug users (IDUs) in Vancouver, Canada. Methods Between 2001 and 2008, eligible participants enrolled in the Vancouver Injection Drug Users Study (VIDUS) completed semi-annual questionnaires that elicited information regarding sociodemographics, drug use patterns, and mental health problems including suicidal behavior. We used Cox proportional hazards models with time-dependent covariates to determine whether self-reported MA injection was an independent predictor of attempting suicide at subsequent time points. Results Of 1873 eligible participants, 149 (8.0%) reported a suicide attempt, resulting in an incidence density of 2.51 per 100 person-years. Participants who attempted suicide were more likely to be younger (median: 35 vs. 40, p<0.01), female (48.3% vs. 35.1%, p<0.01), and of Aboriginal ancestry (43.6% vs. 31.3%, p<0.01). In a Cox proportional hazards model, MA injection was associated with an 80% increase in the risk of attempting suicide (adjusted hazard ratio = 1.80, 95%CI: 1.08 – 2.99, p=0.02). Conclusions These findings suggest that IDUs who inject MA should be monitored for suicidal behavior. Improved integration of mental health and suicide prevention interventions within harm reduction and drug treatment programs may be fruitful.

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

“…Consistent with previous reports (Marshall et al, 2011), the outcome of interest was a dichotomous measure of suicide attempt assessed by the following question: "In the past six months, have you attempted suicide? ".…”

“…Potential confounders included measured variables previously identified as significant correlates of suicide attempt among drug-using populations (Havens et al, 2004;Marshall et al, 2011), and were grouped into two conceptual domains: socio-demographic characteristics and psychosocial stressors. Age, gender and education were assessed as part of the sociodemographic domain.…”

“…Compared to the general population, intravenous drug use carries a nearly 14-fold elevated risk of completed suicide (Wilcox et al, 2004), and PWID are estimated to be four times more likely to experience an attempt compared to non-injection drug users (Darke and Kaye, 2004). Studies conducted in the United States (Havens et al, 2004) and Canada (Marshall et al, 2011) among street-based PWID reported six-month prevalences of suicide attempt of 7.0% and 8.0%, respectively.…”

“…An extensive literature has focused on cocaine- (Darke and Kaye, 2004;Roy, 2001) and heroin-users (Darke et al, 2005;Roy, 2002Roy, , 2010 and reported comparable prevalences of attempted suicide, suggesting that both drugs may carry a similar risk of suicidal behaviors. Investigations conducted among broader drug-using populations noted a positive association between suicide attempt, and use of cocaine (Britton and Conner, 2010) and amphetamine (Marshall et al, 2011). Use of licit noninjectable substances, including sedative-hypnotics and alcohol, which are often co-used by illicit drug users (Darke and Hall, 1995;Public Health Agency of Canada, 2006), has also been reported to be associated with increased odds of attempted suicide (Backmund et al, 2011;Rossow and Lauritzen, 1999).…”

“…Although polysubstance use is highly prevalent among street-based PWID (Leri et al, 2004), few investigations have examined a broad range of commonly used substances within the same study sample (Wines et al, 2004), making it difficult to compare associations with attempted suicide across substances. Moreover, other findings are limited by a lack of control for important confounding factors implicated in suicidal behaviors, such as mental health status (Marshall et al, 2011).…”