The mental status examination is an essential tool that aids physicians in making psychiatric diagnoses. Familiarity with the components of the examination can help physicians evaluate for and differentiate psychiatric disorders. The mental status examination includes historic report from the patient and observational data gathered by the physician throughout the patient encounter. Major challenges include incorporating key components of the mental status examination into a routine office visit and determining when a more detailed examination or referral is necessary. A mental status examination may be beneficial when the physician senses that something is "not quite right" with a patient. In such situations, specific questions and methods to assess the patient's appearance and general behavior, motor activity, speech, mood and affect, thought process, thought content, perceptual disturbances, sensorium and cognition, insight, and judgment serve to identify features of various psychiatric illnesses. The mental status examination can help distinguish between mood disorders, thought disorders, and cognitive impairment, and it can guide appropriate diagnostic testing and referral to a psychiatrist or other mental health professional.