An open clinical trial of fenfluramine in chronic schizophrenia: a pilot study.

The reports of hyperserotonaemia in chronic schizophrenics and the indications that fenfluramine, a serotonin-releasing drug, may be of therapeutic value in hyperserotonaemic autistic children, were the rationale for this clinical trial. Fenfluramine was administered to 4 treatment-resistant chronic schizophrenic in-patients. They were studied for 14 weeks: 2 baseline weeks, 8 on fenfluramine (maximal dose 120 mg/day for 4 weeks) and 4 post-fenfluramine. Plasma levels of fenfluramine and nor-fenfluramine indicated good compliance. Platelet serotonin concentration decreased in all 4 subjects, weight loss was noted in 2. Clinical changes (assessed by rating psychiatric symptoms and ward behaviour) were observed in 3: moderate sustained improvement in 1, a short-lived activation followed by a slight improvement in another, and a brief amelioration with subsequent worsening in the third. The time and pattern of these changes suggest that they were due to fenfluramine.