Frequently, patients present with psychiatric symptoms that turn out to have a medical etiology. Many of these medical mimics are commonly known such as hypoglycemia and myxedema coma but some are less common which makes them more difficult to diagnosis and manage.  This course will focus on some of the less common etiologies of such psychiatric presentations due to a medical cause such as rare toxic exposures, catatonia from medical causes and encephalitis related to NMDA receptor antagonist. Case presentations will be used to illustrate the evaluation and treatment of these disorders.