Depressive & substance use disorders predominate in the psychopathological backgrounds of suicides of all ages. In 5 published studies of consecutive suicides by adolescents & young adults, the average reported rates are 41% for major depression & 48% for substance abuse. Personality disorders have been less consistently reported with rates varying from 10-34% among young suicides. These consist almost exclusively of borderline & antisocial personality disorders. “Pure” personality disorders are rare because of comorbidity with major depression & substance abuse. Follow-up studies of patients with personality disorders also report similar comorbidity among those who die by suicide. Hypothetical explanations are given for this observed comorbidity. (32 refs.) JA