Borderline and schizotypal personality disorders treated with low-dose thiothixene vs placebo

Fifty outpatients with borderline and/or schizotypal personality disorder were randomly allocated to thiothixene (Navane) or placebo treatment that was continued for 12 weeks. The mean daily dosage of thiothixene hydrochloride in the final week of the study was 8.7 mg, a lower dosage than is used in outpatient schizophrenics. Significant drug-placebo differences were found, regardless of diagnosis, on "illusions," "ideas of reference," "psychoticism," "obsessive-compulsive symptoms," and "phobic anxiety," but not on "depression." Thiothixene seems to have more than an antipsychotic effect. Since response to treatment studies are a means for reformulating diagnostic concepts, we suggest a subdiagnosis defined by those symptoms that are drug-responsive, some of which are not included in current diagnostic criteria. Patients with borderline and schizotypal disorder without the foregoing symptoms probably would not profit from thiothixene and might needlessly be placed at risk for adverse drug effects.