The emergency psychiatric evaluation generally occurs in response to thoughts, feelings, or urges to act that are intolerable to the patient, or to behavior that prompts urgent action by others, such as violent or self-injurious behavior, threats of harm to self or others, failure to care for oneself, bizarre or confused behavior, or intense expressions of distress. The aims and specific approaches to the emergency evaluation have been reviewed elsewhere in detail (11–15) and include the following:

• Assess and enhance the safety of the patient and others.

• Establish a provisional diagnosis (or diagnoses) of the mental disorder(s) most likely to be responsible for the current emergency, including identification of any general medical condition(s) or substance use that is causing or contributing to the patient's mental condition.

• Identify family or other involved persons who can give information that will help the psychiatrist determine the accuracy of reported history, particularly if the patient is cognitively impaired, agitated, or psychotic and has difficulty communicating a history of events. If the patient is to be discharged back to family members or other caretaking persons, their ability to care for the patient and their understanding of the patient's needs must be addressed.

• Identify any current treatment providers who can give information relevant to the evaluation.

• Identify social, environmental, and cultural factors relevant to immediate treatment decisions.

• Determine whether the patient is able and willing to form an alliance that will support further assessment and treatment, what precautions are needed if there is a substantial risk of harm to self or others, and whether involuntary treatment is necessary.

• Develop a specific plan for follow-up, including immediate treatment and disposition; determine whether the patient requires treatment in a hospital or other supervised setting and what follow-up will be required if the patient is not placed in a supervised setting.

The emergency evaluation varies greatly in length and may on occasion exceed several hours. Patients who will be discharged to the community after an emergency evaluation may require more extensive evaluation in the emergency setting than those who will be hospitalized. For example, patients who have presented with intoxication or who have received medications in the emergency department may require additional observation to verify their stability for discharge. In other individuals with significant symptoms but without apparent acute risk to self or others, additional time may be needed to obtain more detailed input from family, other involved caretaking persons, and treatment providers; to verify that the proposed plan of follow-up is viable; and to communicate with follow-up caregivers about interventions or recommendations resulting from the emergency assessment.

When patients are agitated, psychotic, or uncooperative with assessment, and when their clinical presentation appears to differ from the stated factors prompting assessment, it may be especially important to obtain history from other individuals (e.g., family members, other professionals, police), keeping in mind principles of confidentiality, as described in Section I.A above and in Section V.A .

Patients presenting for emergency psychiatric evaluation have a high prevalence of combined general medical and psychiatric illness, recent trauma, substance use and substance-related conditions, and cognitive impairment (16–27). These diagnostic possibilities deserve careful consideration. General medical and psychiatric evaluations should be coordinated so that additional medical evaluation can be requested or initiated by the psychiatrist on the basis of diagnostic or therapeutic considerations arising from the psychiatric history and interview. Although issues of confidentiality are sometimes raised, in an emergency situation necessary information about the patient can be communicated with the emergency medicine department staff. In many emergency settings, patients initially are examined by a nonpsychiatric physician to exclude acute general medical problems. Such examinations usually are limited in scope and rarely are definitive (18, 19, 28–30). Furthermore, psychiatrists and emergency physicians sometimes have different viewpoints on the utility of laboratory screening for substance use or medical disorders in psychiatric emergency department patients (31, 32). Therefore, on the basis of clinical judgment and the specific circumstances of the evaluation, the psychiatrist may need to request or initiate further general medical evaluation to address diagnostic concerns that emerge from the psychiatric evaluation (12, 16, 18–27, 33–35).