Brief ReportsThe Effect of Extract of Ginkgo Biloba Added to Haloperidol on Superoxide Dismutase in Inpatients With Chronic SchizophreniaZhang, Xiang Yang MD, PhD; Zhou, Dong Feng MD; Su, Jian Min MD; Zhang, Pei Yan MDAuthor Information Department of Biochemistry, Institute of Mental Health, Beijing Medical University, Beijing, People's Republic of China Received July 12, 1999; accepted after revision January 9, 2000. Drs. Zhang and Zhou made equal contributions to this work. Address requests for reprints to: Xiang Yang Zhang, MD, PhD, SHM B-267, P.O. Box 208066, Department of Psychiatry, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510. Address e-mail to: [email protected]. Journal of Clinical Psychopharmacology: February 2001 - Volume 21 - Issue 1 - p 85-88 Buy Abstract The purpose of the study was to evaluate the effect of the classic antipsychotic haloperidol plus extract of ginkgo biloba (EGb) on treatment-resistant chronic schizophrenia and on blood superoxide dismutase (SOD) levels. Eighty-two patients with chronic refractory schizophrenia were studied. Forty-three patients were treated with haloperidol plus extract of ginkgo biloba (group 1), and 39 received haloperidol plus placebo (group 2). SOD levels of these patients were measured before and after treatment and were compared with SOD levels of 30 healthy volunteers. Therapeutic efficiency was equated with a change in clinical rating scores assessed by standardized measurement tools that included the Scale for the Assessment of Positive Symptoms and the Scale for the Assessment of Negative Symptoms (SANS) over this period. Patients in group 1 improved significantly as demonstrated by scores from these two assessment instruments; those in group 2 improved significantly only as shown by scores on SANS. SOD levels before treatment in all patients were significantly higher than those in healthy controls; after treatment, the SOD level decreased significantly in group 1 but not in group 2. These results suggest that EGb may enhance the efficiency of the classic antipsychotic haloperidol in patients with schizophrenia, especially on their positive symptoms, and that EGb may work through an antioxidant effect that is involved in the therapeutic mechanism in patients with chronic refractory schizophrenia. © 2001 Lippincott Williams & Wilkins, Inc.