Effects of Bromocriptine on Negative Symptoms of Schizophrenia: A Double Blind Clinical Trial

Negative symptoms are still a major obstacle in the recovery of schizophrenic patients. Many attempts to develop novel drugs affecting negative symptoms of schizophrenia have yielded insignificant results. This study evaluates the effects of bromocriptine, a dopamine agonist, on negative symptoms of schizophrenia utilizing a placebo-controlled crossover double-blind clinical trial.
Methodology: To eliminate interfering factors, only patients with significant negative symptoms who did not have signs of depression, drug side effects, active psychosis, significant somatic diseases, substance abuse, or contraindications for bromocriptine were included. Among 61 patients, only 14 fulfilled inclusion criteria, two of them refrained from taking part. Patients were randomly divided into test and placebo groups and were treated for 13 weeks; for 6 weeks the test group received bromocriptine and the other received placebo, followed by a one week wash-out period during which both groups received placebo, after that groups were exchanged. Subjects were treated with 15 milligrams of bromocriptine and tested with Positive and Negative Syndrome Scale (PANSS), which is a standard test for measuring positive and negative symptoms of schizophrenia. Data analyzed using Wilcoxon sign-rank test.
Conclusions: This trial showed that addition of bromocriptine to antipsychotic drugs did not increase the risk of psychosis and reduced negative symptoms of schizophrenia.