Suicide Risk Among Cannabis, Heroin and Cocaine Users

Abstract Individuals who use substances such as cocaine, cannabis, heroin, alcohol and nicotine are at increased risk for suicidal behavior. Our objective is to examine the relationship between substance use and suicide. An observational psychological autopsy study design was used to compare substance use in individuals who died by suicide and individuals who died by other manners. Subjects were recruited at the Medical Forensic Institute of Seville between 2006 and 2018. The total sample was 593 decedents including those who had died by suicide ( n = 412) and those who died suddenly from non-suicidal causes ( n = 181). We determined the association between substance (cannabis, heroin, cocaine, alcohol and nicotine) use and suicide. We also analyzed the behavioral association between the use of any one of these substances (cannabis, heroin, cocaine, alcohol, and nicotine), as well as the use of more than one substance at a time and manner of death (suicide vs not suicide). We established three categories of substance use: never-used, lifetime users (prior use but not in the past month), and past month users (use within the last month). This study found that decedents who died by suicide were more likely to have substance use compared with those who died by other means. Use of cocaine, cannabis, or heroin within the last month prior to death was associated with increased risk of suicide (X2 = 13.050; df = p = 0.001). Of the substances examined, the strongest association was between past month cocaine use and suicide after adjusting for Axis I and Axis II disorders. Our study supports the relationship between the use of illicit substances and suicide. The use of substances, independent of the type, was associated with a greater risk of suicide. Cocaine use had the strongest association with suicide.