Background: There is considerable debate as to whether suicide is more likely to occur early in the course of major depressive disorder or by cumulative risk, with an increasing risk with each subsequent major depressive episode (MDE). By considering the number of MDEs among representative suicides, we aimed to further investigate the relationship between suicide outcome and the course of major depressive disorder.
Method: A psychological autopsy method with best informants was used to investigate 154 consecutive suicides who died in the context of a DSM-IV MDE. Proxy-based interviews were conducted by using the Structured Clinical Interview for DSM-III-R; the Structured Clinical Interview for DSM-IV Axis II; and a series of behavioral and personality-trait assessments. Second, 143 living depressed outpatients of comparable age to the suicide group were assessed for their history of MDEs. The study was conducted between 2000 and 2005.
Results: The distribution of MDEs among depressed suicide completers was as follows: first MDE, 74.7%; second MDE, 18.8%; more than 2 MDEs, 6.5%. This distribution is compared to 32.9% of depressed living outpatients with a single MDE. Increased levels of hostility were associated with single MDE suicide completers. The anxious trait of harm avoidance increased among multiple MDE suicide completers. Alcohol abuse increased among first MDE suicide completers.
Conclusions: Suicide in major depressive disorder is most likely to occur during the first MDE, and this appears to be related to increased levels of the impulsive-aggressive diathesis.