Medical comorbid diagnoses among adult psychiatric inpatients.

•74.9% of psychiatric inpatients on Medicaid have at least one medical comorbidity.•Among psychiatric inpatients aged 18–24, 30% have 2 or more medical diagnoses.•HIV and pulmonary disease disproportionately affect younger psychiatric inpatients.•Women psychiatric inpatients have greater medical burden than men.•Hospitals with <100 beds are more likely to admit patients with medical diagnoses.