Schizotypal personality disorder. Chestnut Lodge follow-up study: VI. Long-term follow-up perspectives.

This study reports the first long-term follow-up of patients with schizotypal personality disorder (SPD) as defined by DSM-III. Patients with the pure syndrome (SPD, n = 10) were compared with patients with schizophrenia (S, n = 53) and borderline personality disorder (BPD, n = 81). Three "mixed" cohorts (S/SPD, n = 61; S/SPD/BPD, n = 30; SPD/BPD, n = 18) were added to investigate the effect of schizotypal disorder on the longitudinal course of comparison groups. Schizotypal personality disorder proved to be common in the Chestnut Lodge follow-up study patients, although it was rare as a pure syndrome. From the perspective of follow-up, SPD appeared related to S but not to BPD. The mixed axis II borderline syndrome (SPD/BPD) had a long-term profile closer to BPD than to SPD, and adding SPD to S appeared (unexpectedly) to enhance outcome.