Among affectively ill patients followed naturalistically for up to 14 years, 36 committed suicide, 120 attempted suicide, and 373 had no recorded suicide attempt. Comparing these three groups on clinical and intake personality revealed that suicide completed within 12 months was predicted by clinical but not personality variables, and suicide beyond 12 months was predicted by newly derived temperament factors, not clinical variables. Attempters and completers shared core characteristics: previous attempts, impulsivity, substance abuse, and psychic turmoil within a cycling/mixed bipolar disorder. Such temperament attributes as impulsivity and assertiveness were the best prospective predictors of completed suicides beyond 12 months with a sensitivity level of 74% and specificity level of 82%.