Effects of fenfluramine on neuropsychological and communicative functioning in treatment-refractory schizophrenic patients.

Reported behavioral improvement among autistic patients following feufluramine treatment and a high serotonin level among certain chronic schizophrenic patients suggested that fenfluramine treatment might be beneficial with such schizophrenic patients, especially within the realm of neuropsychological and communicative functioning. A brief neuropsychological battery was administered to eight chronic schizophrenic subjects before, during, and after fenfluramine treatment. Conversations in controlled settings were audiotaped before and during fenfluramine treatment for seven of these subjects and one additional subject. These language samples were analyzed for communicative competence and evidence of thought disorder. Overall, neuropsychological and communicative functioning was worse under the fenfluramine condition, even though blood serotonin levels were about half those at baseline conditions. The results suggest that it is not the higher levels of blood serotonin by themselves that are related to depressed neuropsychological, communicative, and other functioning. In fact, the higher levels of serotonin may well be related to adaptations for maximal level of functioning. These results suggest caution in the use of fenfluramine for other schizophrenic populations.