Early insulin resistance predicts weight gain and waist circumference increase in first-episode psychosis--A one year follow-up study.

First-episode psychosis (FEP) is associated with weight gain during the first year of treatment, and risk of abdominal obesity is particularly increased. To identify early risk markers of weight gain and abdominal obesity, we investigated baseline metabolic differences in 60 FEP patients and 27 controls, and longitudinal changes during the first year of treatment in patients. Compared to controls at baseline, patients had higher low-density lipoprotein, triglyceride and apolipoprotein B levels, and lower levels of high-density lipoprotein and apolipoprotein A-I but no difference in body mass index or waist circumference. At 12-month follow-up, 60.6% of patients were overweight or obese and 58.8% had abdominal obesity. No significant increase during follow-up was seen in markers of glucose and lipid metabolism or blood pressure, but increase in C-reactive protein between baseline and 12-month follow-up was statistically significant. Weight increase was predicted by baseline insulin resistance and olanzapine use, while increase in waist circumference was predicted by baseline insulin resistance only. In conclusion, insulin resistance may be an early marker of increased vulnerability to weight gain and abdominal obesity in young adults with FEP. Olanzapine should be avoided as a first-line treatment in FEP due to the substantial weight increase it causes. In addition, the increase in the prevalence of overweight and abdominal obesity was accompanied by the emergence of low-grade systemic inflammation.