Weight gain and obesity in schizophrenia: epidemiology, pathobiology, and management

Objective To review recent advances in the epidemiology, pathobiology, and management of weight gain and obesity in patients with schizophrenia and to evaluate the extent to which they should influence guidelines for clinical practice. Method A Medline literature search was performed to identify clinical and experimental studies published in 2005–2014 decade. Results Weight gain and obesity increase the risk of adult‐onset diabetes mellitus and cardiovascular disorders, non‐adherence with pharmacological interventions, quality of life, and psychiatric readmissions. The etiology includes adverse effects of antipsychotics, pretreatment/premorbid genetic vulnerabilities, psychosocial and socioeconomic risk factors, and unhealthy lifestyle. Patients with schizophrenia have higher intake of calories in the form of high‐density food and lower energy expenditure. The inverse relationship between baseline body mass index and antipsychotic‐induced weight gain is probably due to previous antipsychotic exposure. In experimental models, the second‐generation antipsychotic olanzapine increased the orexigenic stimulation of hypothalamic structures responsible for energy homeostasis. Conclusion The management of weight gain and obesity in patients with schizophrenia centers on behavioural interventions using caloric intake reduction, dietary restructuring, and moderate‐intensity physical activity. The decision to switch antipsychotics to lower‐liability medications should be individualized, and metformin may be considered for adjunctive therapy, given its favorable risk‐benefit profile.