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  • Review the increased mortality for people with severe mental illness (SMI).

  • Discuss common medical comorbidities among people with SMI, including cardiovascular disease, metabolic syndrome, nicotine dependence, substance abuse, HIV, and hepatitis C.

  • Discuss common psychiatric comorbidities among people with medical conditions, including depression, anxiety, and substance abuse.

  • Review effective health-care delivery models for integrating primary care and behavioral health.


Almost 1 billion people worldwide and over 25% of US adults suffer from a mental illness.1 Those with mental illness have higher rates of death, disability, medical illness, incarceration, homelessness, unemployment, poverty, and violation of their human rights. Exposure to humanitarian crises, natural disasters, violence, poverty, and chronic illness increase the likelihood of mental illness.

Lack of access to mental illness care is very common—treatment rates range from 13% to 33% in high-income countries, and from 5% to 13% in low- and middle-income countries.2 When mental illness co-occurs with other medical conditions, it complicates treatment of both conditions. Unfortunately, even with access to care, medical disorders in people with severe mental illnesses (SMIs) often go undiagnosed and untreated, and conversely, mental disorders in people with medical conditions often go undiagnosed and untreated. Overall, medical costs are higher for people with mental illness.3,4 For example, people with diabetes and comorbid depression have health-care costs that are 4.5 times higher than those without depression.4

Since the majority of people with mental illnesses are served in primary care, this chapter is dedicated to helping primary care providers improve the medical care received by this vulnerable population.5 First, we review common medical comorbidities of people with SMIs and suggest guideline-concordant screening and treatment strategies. Second, we discuss the psychiatric comorbidities commonly afflicting people with medical conditions, and suggest screening tools to identify these illnesses. Third, since many people with HIV are treated in primary care, we have a special section dedicated to psychiatric comorbidities among people living with HIV. Finally, we discuss models for integration of mental and physical health that can assist administrators of health-care systems serving these patients. Although we concentrate on the US population, many of the issues we raise have relevance globally as well.


Ms. Jones is a 35-year-old African-American woman with schizophrenia and a history of multiple psychiatric hospitalizations. She has limited insight into her mental health condition, but does take risperidone 2 mg twice a day. She presents to the primary care clinic at the urging of her case manager.

In 2012, the prevalence of SMI (e.g., schizophrenia, schizoaffective disorder, bipolar disorder) was approximately 4% of the US population, or 9.6 million people nationwide.6 Although the majority of these patients are cared for in specialty mental health-care settings, primary care physicians—particularly those serving safety-net populations—often provide care ...

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