Researchers have found that drug users who inject methamphetamine had an 80% greater risk of attempting suicide than drug users who inject other substances.
Although the causal pathway between injecting methamphetamine and suicidal behavior requires further investigation, study authors suggest that it likely involves a combination of neurobiological, social, and structural mechanisms, at least in the population studied.
The results of the study, by Columbia University's Mailman School of Public Health and the University of British Columbia, are published in the December issue of Drug and Alcohol Dependence.
"Compared to other injection drug users, it is possible that methamphetamine users are more isolated and have poorer social support systems," said lead author Brandon Marshall, PhD, a postdoctoral fellow at the Mailman School of Public Health and research coordinator for the Urban Health Research Initiative in British Colombia. "The high rate of attempted suicide observed in this study suggests that suicide prevention efforts should be an integral part of substance abuse treatment programs," said Dr. Marshall. "In addition, people who inject methamphetamine but are not in treatment would likely benefit from improved suicide risk assessment and other mental health support services within health care settings."
The Vancouver Injection Drug Users Study is part of the ongoing British Columbia Centre for Excellence in HIV/AIDS' Urban Health Research Initiative, which focuses on the effects of substance use, infectious diseases, and the urban environment on the health of urban populations. Vancouver's Downtown Eastside is known as a center for illicit drug use, and fatalities from drug overdoses and drug-related violence are common. A large outbreak of HIV infection reported there in 1997 was among the fastest spreading HIV epidemics in the developed world.
Participation in the seven-year study, which ended in May 2008, was through word of mouth, street outreach, and referrals and included an interviewer-administered questionnaire on sociodemographic characteristics, drug use, treatment utilization, and HIV risk behaviors. The researchers evaluated 1,873 participants whose median age was 31, while 36.2% of participants were female, and 32.1% were of Aboriginal ancestry. In total, 8% percent of study participants reported a suicide attempt.
"This is one of North America's largest cohorts of injection drug users, and the research is among the first longitudinal studies to examine attempts of suicide by injection drug users," said Dr. Marshall. "Most of these 5,000 users are concentrated in a very small neighborhood, making it a logical environment for this type of study. Because our study is one of the main points of access to health care for this population, this is a very well utilized study with a high rate of follow-up."
Dr. Marshall and colleagues also discovered that infrequent methamphetamine injection was a predictor of attempting suicide, while frequent methamphetamine injection was associated with the greatest risk of attempting suicide.