Abstract
Objective
To investigate the effects of Ginko biloba extract (EGb) administration on T lymphocyte subsets and superoxide dismutase (SOD) levels in schizophrenia.
Methods
One hundred and nine schizophrenic inpatients were randomly assigned to 12 weeks of treatment with 360 mg/day of EGb plus a stable dose of 0.25 mg kg−1 day−1 of haloperidol and placebo plus the same dose of haloperidol using a double-blind design. Clinical efficacy was determined using the Brief Psychiatric Rating Scale (BPRS), Scale for Assessment of Positive Symptoms, and Scale for Assessment of Negative Symptoms. T lymphocytes (CD3+), T helper cells (CD4+), T suppressor cells (CD8+), and IL-2-secreting cells were measured using the alkaline phosphatase/antialkaline phosphatase technique; and SOD levels were measured by radioimmunometric assay at baseline and at posttreatment, as compared to 30 sex- and age-matched normal subjects.
Results
Patients demonstrated significantly lower CD3+, CD4+, and IL-2-secreting cells, together with CD4/CD8 ratio, and significantly higher blood SOD levels than did healthy controls at baseline. There was a significantly negative relationship between SOD and CD4+ cells in the schizophrenic group at baseline. After a 12-week treatment, CD3+, CD4+, and IL-2-secreting cells, together with CD4/CD8 ratio, showed a significant increase, but a significant decrease in SOD levels in the EGb group. There was only a significant increase in CD4+ cells but no change in SOD levels in the placebo group. There was a significant correlation between the change in CD4+ cells at posttreatment vs pretreatment and a reduction of BPRS total score in the whole patient group.
Conclusions
EGb may improve the decreased peripheral immune functions in schizophrenia. The beneficial effects of EGb on the immune systems and the improvement of schizophrenic symptoms may be medicated through its antioxidant activity.
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Acknowledgement
This study was supported by the Beijing Scientific and Technological New Stars Fund, Beijing, China (Dr. X. Y. Zhang).
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Zhang, X.Y., Zhou, D.F., Cao, L.Y. et al. The effects of Ginkgo biloba extract added to haloperidol on peripheral T cell subsets in drug-free schizophrenia: a double-blind, placebo-controlled trial. Psychopharmacology 188, 12–17 (2006). https://doi.org/10.1007/s00213-006-0476-2
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DOI: https://doi.org/10.1007/s00213-006-0476-2