Predictors of serious suicidal behavior in late-life depression

The present study aimed to identify pathways to suicidal behavior in late life that can guide identification of those most at risk and improve treatment. In a longitudinal study of late-life depression, we prospectively assessed risk factors specifically associated with fatal and near-fatal as compared to less lethal suicidal behavior. We enrolled 401 participants (age 66+9.9): 311 with unipolar non-psychotic depression and 90 non-psychiatric controls. The median follow-up was 5.4 years. Results indicated that history of suicide attempt predicted a two-fold increase in the risk of dying from natural causes. In univariate models, male gender, higher income, current depression and current and worst lifetime suicidal ideation severity, cognitive control deficits, and low levels of non-planning impulsivity predicted fatal and near-fatal suicidal behavior. In contrast, incident less lethal suicidal behavior was mostly associated with maladaptive personality traits, impulsivity, and severity of psychiatric illness in univariate models. In multipredictor models, male gender, worst lifetime suicidal ideation, and deficits in cognitive control independently predicted fatal/near-fatal suicidal behavior, while introversion, history of suicide attempt, and earlier age of onset of depression predicted less lethal suicidal behavior. While clinicians may be familiar with suicide risk factors identified in younger samples such as dysfunctional personality, impulsivity, and co-morbid substance use, in late life these characteristics only pertain to lower-lethality suicidal behavior. Cognitive control deficits, which likely play a greater role in old age, predict serious suicidal behavior.