The Effect of Extract of Ginkgo Biloba Added to Haloperidol on Superoxide Dismutase in Inpatients With Chronic Schizophrenia

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.

Ginkgo biloba leaf extract (EGb 761) enhances catalepsy induced by haloperidol and L-nitroarginine in mice

“…For neuroleptics such as haloperidol these effects are related to their clinical efficacy. It is therefore interesting that, similar to the facilitation of the cataleptic effect of haloperidol detected in this study, Zhang et al (16) showed an improvement of positive symptoms after the administration of EGb 761 plus haloperidol to patients with chronic refractory schizophrenia. The authors attributed this therapeutic effect to a plausible antioxidant action of EGb 761, since it was correlated with a decrease in blood levels of superoxide dismutase, one of the scavenging enzymes that detoxifies free radicals.…”

Imbalanced free radicals and antioxidant defense systems in schizophrenia: A comparative study

“…Nevertheless, high intake of sufficient vitamin E dietary supplementation is beneficial for scavenging free radicals, and can keep the dynamic balance between oxidation and antioxidation (Mahadik et al, 2001) and thus it may improve outcome and prognosis of schizophrenia. Studies developed by Zhang et al(2001a; indicated that ginkgo biloba adds haloperidol attribute to chronic or resistant schizophrenia. And supplementation of vitamin C with atypical antipsychotics can reduce oxidative stress and improve the outcome of schizophrenia (Dakhale et al, 2005).…”

“…Some studies (Taneli et al, 2004;Yao et al, 1998a;1998b;1999;2000b;Zhang et al, 2006) indicated that antipsychotic drugs have no significant regulatory action on the antioxidative defense system. However, more studies revealed that antioxidant enzyme activities are associated with the treatment of schizophrenic patients with different neuroleptics Pillai et al, 2006;Reddy et al, 2003;Vaiva et al, 1994;Yao et al, 1998b;Zhang et al, 2001a;2003b). While these researches mainly focused on a few critical antioxidant enzymes and chronic, drug-medicated schizophrenia, the evidence is not consistent and sufficient.…”

Oxidative stress in psychiatric disorders: evidence base and therapeutic implications

“…This group also showed superior improvements in peripheral T cell subsets (CD3+, CD4+, CD8+ and IL-2-secreting cells), which were diminished at baseline (Zhang et al, 2006b). These authors additionally reported elevated pre-treatment SOD levels among patients with treatment-resistant schizophrenia, correlating with positive symptomatic severity, which was selectively reduced in patients receiving EGb but not placebo (Zhang et al, 2001a(Zhang et al, , 2006bZhou et al, 1999), thereby suggesting that antioxidant activity, schizophrenia symptoms and peripheral immune functions may be interrelated. A confounder in this group of studies is the use of haloperidol as treatment base, which through its potential in inducing oxidative stress and cognitive blunting, may have added iatrogenic complexities to the disease and treatment process, such that it is difficult to determine whether the superior outcomes were due to lessened adverse effects, underlying psychopathology, or both.…”