Suicide Attempts in Major Affective Disorder Patients With Comorbid Substance Use Disorders

Background: The widely accepted impression that substance abuse and dependence are associatedwith increased suicidal risk was evaluated by literature review and with new data. Method: Previous research on this association was reviewed, and clinical data on suicide attempts and substance use in504 mood disorder patients hospitalized in 4 psychiatric units in Sardinia affiliated with the Italianmental health system were analyzed. Results: The literature supports associations of alcohol and drug use comorbidity with major affective disorders, and of some substances (polyabuse, alcohol, heroin,cocaine, and even tobacco, but perhaps not marijuana or hallucinogens) with suicidal behavior. Ournew findings generally supported these 2-way associations. Suicidal risks were similar in hospitalizedmen and women but were associated with bipolar II, bipolar I (mainly mixed), and unipolar depressivedisorders as well as substance abuse, with little effect of type of agent. Substance abuse was morecommon in nonmixed bipolar disorders, men, and age below 30. Conclusion: The tendency for bipolar I, mainly nonmixed patients, to have a relatively high risk of substance abuse and low risk ofsuicide attempts indicates that mainly depressive or dysphoric (bipolar II, nonbipolar, and bipolar I,mainly mixed) mood disorders may be especially lethal. Differences in risks of substance abuse andsuicidal behavior in men and in bipolar I patients further suggest that substance abuse and mood disordersmay contribute to suicidal risk with at least partial independence or additivity.