Patients with psychiatric illnesses account for one out of every eight visits to the emergency department (ED), with the most frequent presenting problems being depression, followed by anxiety, substance use disorders, other mood disorders, and psychosis (Agency for Healthcare Research and Quality, 2010). When these patients present to the ED in crisis, meaning a situation requiring immediate intervention, the crisis situation commonly involves severe agitation, or behavior that poses a risk to the safety of the patient or others, including suicide, and threatening or engaging in violence. This course will therefore focus primarily on how ED providers can provide effective assessment and treatment to individuals with these types of behavioral health emergencies.