The effect of extract of ginkgo biloba addition to olanzapine on therapeutic effect and antioxidant enzyme levels in patients with schizophrenia

Abstract

It has been suggested that the extract of gingko biloba (EGb) may enhance the efficiency of the classic antipsychotic haloperidol in patients with chronic schizophrenia, especially on positive symptoms, and reduce serum superoxide dismutase (SOD) levels. Therefore, we decided to evaluate the therapeutic effect of EGb and to examine the effect of it on the levels of antioxidant enzymes in schizophrenic patients on olanzapine treatment. We hypothesized that EGb would have the beneficial effects on schizophrenic symptoms and might cause reductions in antioxidant enzymes. The subjects were randomly assigned to the two groups: olanzapine plus EGb (group I) ( n = 15) and olanzapine alone (group II) ( n = 14). The patients were evaluated at baseline and at week 8 with respect to the Positive and Negative Syndrome Scale (PANSS), serum SOD, catalase (CAT), and glutathion peroxidase (GPX) levels. At baseline, no statistically significant difference regarding the mean total PANSS scores between treatment groups was found. At the evaluation of week 8, a significant difference in mean Scale for the Assessment of Postive Symptoms (SAPS) scores but not in Scale for the Assessment of Negative Symptoms scores between groups was found. Total patients had statistically significant higher serum SOD, CAT and GPX levels compared to control groups at baseline. At 8 weeks, there were significant differences in the mean decrease in SOD and CAT levels but not in GPX levels between treatment groups. The changes in SOD and CAT levels were correlated with the change in SAPS in group I, but not in the group II . The present study supported the findings of the previous study demonstrating that EGb might enhance the efficiency of antipsychotic in patients with schizophrenia, particularly on positive symptoms of the disorder.

Review and meta-analysis of usage of ginkgo as an adjunct therapy in chronic schizophrenia

“…Out of 14 search results, eight (Atmaca et al 2005;Doruk et al 2008;Lin et al 2007;Luo et al 1997;Zhang et al 2001Zhang et al a, b, 2006bZhou et al 1999) came from the PubMed database, three (Knable, 2002;Werneke, 2008;Werneke et al 2006) from other electronic databases, and three (Chen et al 1997;Meng et al 1996;Xu et al 2002) from crossreferencing of the electronically searched articles. Out of these, one was a case report (Lin et al 2007), one (Zhang et al 2006b) was unrelated to the subject matter, and three (Knable, 2002;Werneke, 2008;Werneke et al 2006) were review publications.…”

“…Attempts to contact the author for further clarification did not materialize and hence therefore only one (Zhang et al 2001 b) of those three publications (Zhang et al 2001a, b;Zhou et al 1999) was included. Accordingly a final list of seven studies were deemed suitable for further evaluation (Atmaca et al 2005;Chen et al 1997;Doruk et al 2008;Luo et al 1997;Meng et al 1996;Xu et al 2002;Zhang et al 2001b). From this list of seven articles, four were in Chinese language and were translated by one of the authors (K.C.)…”

Oxidative stress in psychiatric disorders: evidence base and therapeutic implications

“…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. This concern was minimized in a subsequent placebocontrolled trial of EGb adjunctive to olanzapine, which also found significantly lower SAPS scores, SOD and CAT levels among the EGb group, although this study had other limitations, such as its singleblinded design and underpowered sample size (n=29) (Atmaca et al, 2005).…”

Refining and integrating schizophrenia pathophysiology – Relevance of the allostatic load concept

“…In addition, there are studies showing the efficacy of adjunctive treatment with some antioxidants. It has been found that add-on therapies with ginkgo biloba (Atmaca et al, 2005;Doruk et al, 2008;Zhang et al, 2001a,b), melatonin (Anderson and Maes, 2012), vitamins C and E (Reddy, 2011), N-acetylcysteine (Berk et al, 2013;Dean et al, 2011) and polyunsaturated fatty acids (Das, 2013) might be beneficial in terms of alleviating positive and negative symptoms, cognitive deficits, circadian rhythm disturbances and extrapyramidal symptoms.…”