Minimally Treated Patients With Psychosis Have Lower BMI

A man measuring his waist
A man measuring his waist
Researchers found that diet and physical activity should be further investigated as confounders in measuring obesity in patients with schizophrenia.

Patients with minimally treated psychosis have a higher waist-to-hip ratio (WHR) but a lower body mass index (BMI) compared with healthy individuals, a new study found. The study findings were published in Schizophrenia Research.

Investigators performed a systematic review of studies reporting associations between obesity measures and psychosis. Inclusion criteria were any articles published between 1860 and May 2018; had both patients with schizophrenia and healthy controls; and featured a cross-sectional, longitudinal, review, or case report design. A total of 23 studies were identified and subsequently included in the final meta-analysis. Measures of BMI, waist circumference (WC), and WHR were reported in 23, 9, and 5 participants, respectively. Sensitivity analyses were performed to evaluate the impact of age, sex, ethnicity, antipsychotic exposure, and schizophrenia-related psychosis on standardized mean differences (SMDs).

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The pooled analysis revealed a lower BMI in antipsychotic-naïve and minimally treated patients with psychosis compared with healthy controls (SMD, −0.19; 95% CI, −0.34 to −0.05; P =.009). In the sensitivity analysis, BMI remained lower in patients vs healthy controls (SMD, −0.26; 95% CI, −0.51 to −0.00; P =.05). There were no differences between antipsychotic-naïve and minimally treated patients with psychosis and health controls in terms of WC (SMD, −0.07; 95% CI, −0.17-0.32; P =.55). A higher WHF was observed in antipsychotic-naïve and minimally treated patients with psychosis vs healthy controls (SMD, 0.34; 95% CI, 0.14-0.55; P =.001).

Study limitations included the researchers’ inability to adjust for potential confounders related to obesity, the heterogeneity of schizophrenia and other psychotic disorders in the cohort, and the reliance on only BMI and WC data for identifying obesity.

“Future studies are required to explore the mechanisms underlying alterations in obesity measures in patients with psychosis, independent of antipsychotic effects,” the researchers concluded. “An improved understanding of these differences could guide strategies for monitoring weight gain in patients with schizophrenia.”


Shah P, Iwata Y, Caravaggio F, et al. Alterations in body mass index and waist-to-hip ratio in never and minimally treated patients with psychosis: A systematic review and meta-analysis [published online January 23, 2019]. Schizophr Res. doi: 10.1016/j.schres.2019.01.005