Excessive insulin secretion in Japanese schizophrenic patients treated with antipsychotics despite normal fasting glucose levels

Effects of nutritional education on weight change and metabolic abnormalities among patients with schizophrenia in Japan: A randomized controlled trial

OBJECTIVE

Patients with schizophrenia have a higher prevalence of metabolic syndrome (MetS) than the general population. Minimizing weight gain and metabolic abnormalities in a population with an already high prevalence of obesity is of clinical and social importance. This randomized controlled trial investigated the effect of monthly nutritional education on weight change and metabolic abnormalities among patients with schizophrenia in Japan.

METHODS

From July 2014 to December 2014, we recruited 265 obese patients who had a DSM-IV diagnosis of schizophrenia or schizoaffective disorder. Participants were randomly assigned to a standard care (A), doctor's weight loss advice (B), or an individual nutritional education group (C) for 12 months. The prevalence of MetS and body weight were measured at baseline and 12 months.

RESULTS

After the 12-month treatment, 189 patients were evaluated, and the prevalence of MetS based on the ATP III-A definition in groups A, B, and C was 68.9%, 67.2%, and 47.5%, respectively. Group C showed increased weight loss (3.2 ± 4.5 kg) over the 12-month study period, and the change in weight differed significantly from that of group A; additionally, 26.2% of the participants in group C lost 7% or more of their initial weight, compared with 8.2% of those in group A.

CONCLUSION

Individual nutrition education provided by a dietitian was highly successful in reducing obesity in patients with schizophrenia and could be the first choice to address both weight gain and metabolic abnormalities induced by antipsychotic medications.

Does the Time of Drug Administration Alter the Metabolic Risk of Aripiprazole?

Antipsychotic drugs cause metabolic abnormalities through a mechanism that involves antagonism of D₂ dopamine receptors (D₂R). Under healthy conditions, insulin release follows a circadian rhythm and is low at night, and in pancreatic beta-cells, D₂Rs negatively regulate insulin release. Since they are sedating, many antipsychotics are dosed at night. However, the resulting reduction in overnight D₂R activity may disrupt 24 h rhythms in insulin release, potentially exacerbating metabolic dysfunction. We examined retrospective clinical data from patients treated over approximately 1 year with the antipsychotic drug aripiprazole (ARPZ), a D2R partial agonist. To identify effects of timing on metabolic risk, we found cases treated with ARPZ either in the morning (n = 90) or at bedtime (n = 53), and compared hemoglobin A1c, and six secondary metabolic parameters across the two groups. After controlling for demographic and clinical factors, patients treated with ARPZ at night had a significant decrease in HDL cholesterol, while in patients who took ARPZ in the morning had no change. There was a non-significant trend toward higher serum triglycerides in the patients treated with ARPZ at night vs. morning. There were no group differences in hemoglobin A1c, BMI, total cholesterol, LDL cholesterol, or blood pressure. Patients taking APPZ at night developed a worse lipid profile, with lower HDL cholesterol and a trend toward higher triglycerides. These changes may pose additional metabolic risk factors compared to those who take ARPZ in the morning. Interventions based on drug timing may reduce some of the adverse metabolic consequences of antipsychotic drugs.

Metabolomic profiling of schizophrenia patients at risk for metabolic syndrome

Second-generation antipsychotics (SGAs) are commonly used to treat schizophrenia. However, SGAs cause metabolic disturbances that can manifest as metabolic syndrome (MetS) in a subset of patients. The causes for these metabolic disturbances remain unclear. We performed a comprehensive metabolomic profiling of 60 schizophrenia patients undergoing treatment with SGAs that puts them at high (clozapine, olanzapine), medium (quetiapine, risperidone), or low (ziprasidone, aripiprazole) risk for developing MetS, compared to a cohort of 20 healthy controls. Multiplex immunoassays were used to measure 13 metabolic hormones and adipokines in plasma. Mass spectrometry was used to determine levels of lipids and polar metabolites in 29 patients and 10 controls. We found that levels of insulin and tumor necrosis factor alpha (TNF-α) were significantly higher (p < 0.005) in patients at medium and high risk for MetS, compared to controls. These molecules are known to be increased in individuals with high body fat content and obesity. On the other hand, adiponectin, a molecule responsible for control of food intake and body weight, was significantly decreased in patients at medium and high risk for MetS (p < 0.005). Further, levels of dyacylglycerides (DG), tryacylglycerides (TG) and cholestenone were increased, whereas α-Ketoglutarate and malate, important mediators of the tricarboxylic acid (TCA) cycle, were significantly decreased in patients compared to controls. Our studies suggest that high- and medium-risk SGAs are associated with disruption of energy metabolism pathways. These findings may shed light on the molecular underpinnings of antipsychotic-induced MetS and aid in design of novel therapeutic approaches to reduce the side effects associated with these drugs.