Characterization of impulsivity in suicide completers: clinical, behavioral and psychosocial dimensions.

BACKGROUND Impulsivity is a personality trait thought to be linked to suicide. Yet, not all suicides are highly impulsive. We aimed to better understand clinical, behavioral and psychosocial correlates of the association between suicide and impulsive behavior. METHODS One hundred sixty four suicide cases with impulsivity scores based on the Barratt Impulsivity Scale (BIS) were investigated. To examine the most extreme phenotypes, one hundred suicide cases, representing subjects with BIS scores above the 70th percentile and below the 30th percentile, were compared on clinical, behavioral and psychosocial suicide risk factors assessed by way of structured psychological autopsy methods with best informants. RESULTS The impulsive suicide cases were significantly younger, exhibited higher measures of aggressive behavior, and were more likely to have a cluster B diagnosis as well as lifetime and 6-month prevalence of alcohol and drug abuse/dependence. They also differed significantly from their non-impulsive counterparts on all subscales of the TCI except for Harm Avoidance and Reward Dependence. Impulsive suicide completers were more likely to have had a history of childhood abuse and to have experienced a triggering life event up to a week preceding their death. A multivariate analysis indicated that 6-month prevalence of substance abuse/dependence and high aggressive behavior remained significant even after controlling for other significant variables. LIMITATIONS This study was carried out using proxy-based interviews. CONCLUSIONS Most of the known clinical and behavioral risk factors commonly associated with suicide are particularly valid for impulsive suicide completers. Further, triggering and adverse life events seem to play a role primarily in impulsive suicide.