Five patients with borderline personality disorder (BPD) and 5 patients with schizotypal personality disorder (SPD) completed at least 3 weeks of treatment with amoxapine. The patients fulfilled DSM-III criteria for borderline disorders and scored 7 points or more in Gunderson's Diagnostic Interview for Borderlines (DIB). The final median medication in patients with BPD was 200 mg amoxapine/day and 42 mg oxazepam/day. Duration of treatment averaged 28 days. In patients with SPD the corresponding figures were 250 mg amoxapine/day, 36 mg oxazepam/day and 39 days. The study suggests that amoxapine improves schizophrenic-like and depressive symptoms in patients with schizotypal personality disorders (SPD). No effect could be shown in patients with borderline personality disorders (BPD).