Green Tea Extract for Obesity of Psychiatric Patients: a Double Blind Placebo-controlled Trial

Prevalence of obesity or metabolic syndrome and diabetes:

Obesity or metabolic syndrome is becoming a global epidemic and common health problem. The rising prevalence of obesity and associated comorbidities such as type 2 diabetes, cardiovascular disease, and certain cancers represents a major threat to public health worldwide. In a recent study in Asian populations, the result showed a strong association between BMI and prevalence of diabetes. From the results of a general population survey in Taiwan, the overall prevalence of obesity (body mass index (BMI) ≧ 27 kg/m2) in men and women was 19.2% and 13.4%, respectively, while the age-standardized prevalence of MS was 15.7% by the modified Adult Treatment Panel III criteria, 14.3% by the International Diabetes Federation for Chinese criteria and 16.4% by the metabolic syndrome criteria for Taiwanese. Their data also showed that the prevalence of obesity and metabolic syndrome significantly increased with age (trend test, p < 0.0001) in men and women. The risk of metabolic syndrome and its components increased significantly with BMI, and showed a marked increase with BMI≧24 kg/m2.

Prevalence of obesity or metabolic syndrome and diabetes in psychiatric patients:

The prevalence of MS among patients with schizophrenia or other psychotic disorder has been reported to be high, ranging from 24% to 43% in males and from 27% to 52% in females in previous large-scale investigations. These metabolic abnormalities can be regarded as medical comorbidities, and have an impact not only on physical health and increased hospital length of stay, but also on a lower functional outcome, low self-esteem and poorer quality of life and lead to non-compliant to antipsychotics.

In Taiwan, a large scale survey on 650 patients with schizophrenia or schizoaffective disorder from 36 community psychiatric rehabilitation centers or hospital-affiliated day hospitals in Taipei area revealed an overall metabolic syndrome prevalence of 34.9%, with 38.9% in female and 31.5% in male patients, respectively. The difference of metabolic syndrome prevalence between those patients and the general population was marked in male patients under 40 years of age and in female patients under 50. The authors suggested that BMI≧24 kg/m2 and age over 40 years old are two important risk factors of metabolic syndrome. Since the implementation of second generation antipsychotics (SGAs), especially clozapine, olanzapine or quetiapine, the metabolic syndrome prevalence exaggerated. Bai and her associates (2009) carried a large survey on 567 hospitalized of patients with schizophrenia under SGAs (clozapine =231, olanzapine n=94 and risperidone =242) for an average duration of 45.8+/-27.8 months, and revealed the prevalence of metabolic syndrome among all subjects was 23.8%. The clozapine group had a higher prevalence of metabolic syndrome (28.7%) than did the olanzapine (24.2%) and risperidone groups (19.5%) (P=0.039), and the clozapine group had lower levels of adiponectin (8.46+/-6.02 mg/mL) than did the olanzapine (10.26+/-4. 9 mg/mL) and risperidone groups (10.69+/-7.43 mg/mL) (P=0.001). The authors also found that adiponectin level was negatively correlated with BMI increase after initiation of SGAs treatment. Beside the increase use of SGAs, the use of mood stabilizers such as lithium or valproic acid in patients with bipolar disorder can also lead to body weight increment and metabolic syndrome.