This study examines the roles of post-traumatic stress disorder (PTSD) and drug dependence in non-fatal suicidality, i.e., suicidal ideation and suicide attempt, among Vietnam veterans in their adult years. The sample includes male veterans deployed to Vietnam, including an oversample of those who tested positive for opiates at their return (n = 642). PTSD, substance abuse, suicidality, and other psychopathology are analyzed using three waves of survey and military data covering the time period from early adolescence to middle adulthood. Measures include the onset and recency of each of the lifetime DSM-IV PTSD symptom criteria, and yearly symptom measures of DSM-IV dependence for alcohol and eight classes of psychoactive substances. Survival and hazard models are applied to assess the effects of drug dependence, PTSD, and other psychopathology on the duration of suicidality. Longitudinal models estimate the casual relationships among PTSD, drug dependence, and suicidality over a 25-year period. Results show evidence of strong continuity of PTSD, drug dependence, and suicidality over time. The causal role of drug dependence on PTSD and suicidality is limited to young adulthood. Evidence is stronger for self-medication in later adulthood. The results indicate that a life course perspective is needed for the combined treatment of PTSD and drug dependence for severely traumatized populations.