Purpose of review
To address gaps identified in earlier reviews, namely, the comparative influence of substance use on attempted suicide and completed suicide; the proximal role of substance use as a trigger of suicidal behaviour; the association between substances and suicidal behaviour; suicide and substance use disorders in youth; and the influence of combinations of risk factors, including psychiatric morbidity, on suicide.
The presence of an alcohol use disorder is confirmed as a distal risk factor for completed suicide, as well as attempted suicide. Alcohol use at the time of the suicide attempt is associated with low-risk methods. The use of other substances as a trigger of suicidal behaviour is highlighted in recent studies, but the circumstances leading to the suicidal act and the direct influence of substances in suicidal behaviour need to be explored further. Inhalant use and cocaine use are particularly associated with suicidal behaviour. Young people with multiple risk behaviours, such as substance use and risky sexual behaviours, are at high risk for suicidal behaviour. Psychiatric comorbidity with substance use escalates the risk for suicidal behaviour. Environmental interventions, such as reduction in the number of bars, may be helpful in reducing alcohol-related morbidity, including suicides.
Prevention strategies for reducing suicidal behaviour among substance users need to be prioritized at the individual and the national level through effective design, policy and implementation.