One hundred inpatients admitted to a substance abuse program were diagnosed for personality disorder and were followed up for substance use and adjustment 12 months after discharge. Use of all substances declined significantly. The personality disorder group had significantly greater decreases in the use of marijuana, amphetamines, and LSD, whereas the non‐personality disorder group had significantly greater decreases in the use of wine, beer, and hard liquor. The non‐personality disorder group was significantly more satisfied with their lives compared with the personality disorder group. Differentiated treatment approaches for patients with personality disorders may enhance long‐term response to trea