Patients with schizophrenia have a significantly shorter life expectancy than the general population, and they commonly have an unhealthy lifestyle, which can lead to obesity and metabolic syndrome. The prevalence of obesity, hypertension, hyperlipidemia, and diabetes mellitus, which constitute metabolic syndrome, needs to be examined in patients with schizophrenia, but there have been few large-scale studies carried out in Japan. Thus, the aim of our study was to address this need.
 We conducted a large-scale investigation of the prevalence of obesity, hypertension, hyperlipidemia, and diabetes mellitus using a questionnaire at 520 outpatient facilities and 247 inpatient facilities belonging to the Japan Psychiatric Hospital Association between March 2012 and May 2013. There were 7,655 outpatients and 15,461 inpatients with schizophrenia. The outpatients had a significantly higher prevalence of obesity, hypertension, hypertriglyceridemia, hyper-LDL cholesterolemia, and diabetes mellitus than the inpatients. The prevalence of hypo-HDL cholesterolemia was higher in inpatients than in outpatients.
 Japanese outpatients with schizophrenia were more likely to have physical risks, such as obesity, hypertension, hyperlipidemia, and diabetes mellitus, than the inpatients. The physical risks of patients with schizophrenia may be affected by environmental parameters such as type of care. The physical risks of Japanese patients with schizophrenia require further study.
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