Poverty, substandard medical care, social neglect or withdrawal, unhealthy lifestyle -- these are just some of the contributors to the substantial morbidity of patients with severe mental illness. Medical deteriorations are often unexpected and severe, and particularly difficult to evaluate in the context of psychotic disorders. For this new edition, the Handbook of Medicine in Psychiatry has been updated and streamlined to provide a realistic approach to the medical issues encountered in psychiatric practice by helping clinicians answer whether their patient: Is at risk of dying or becoming severely disabled. Requires an immediate therapeutic intervention for a potentially life-threatening condition. Needs to be transferred to an emergency medicine setting. Requires urgent investigations. Must have changes made in the current medication regimen. Clinical vignettes for each chapter illustrate the complexity of the presentation of abnormal vital signs and somatic disorders in psychiatric settings, including fever, hypertension, seizures, and nausea and vomiting. The guide also provides risk stratification for major complications -- from abnormal thyroid function and acute kidney injury to myocarditis and venous thromboembolism -- enabling readers to determine the need for a transfer of the patient to an emergency medicine setting. A brand-new section features thorough discussions of topics requiring interdisciplinary collaboration with geriatricians, neurologists, anesthesiologists, addiction medicine, and adolescent medicine specialists. Clinicians working in today's busy inpatient and outpatient psychiatric settings will find in these pages a cognitive framework and knowledge base that will aid them in accurate decision making in the conditions of uncertainty created by potentially major medical deteriorations of the vulnerable populations under their care.