Psychiatrists are medical doctors who can order or perform a full range of medical laboratory and psychological tests which, combined with discussions with patients, help provide a picture of a patient's physical and mental state. Their education and clinical training equip them to understand the complex relationship between emotional and other medical illnesses and the relationships with genetics and family history, to evaluate medical and psychological data, to make a diagnosis, and to work with patients to develop treatment plans.
Specific diagnoses are based on criteria established in APA's Diagnostic and Statistical Manual of Mental Disorders(DSM-5), which contains descriptions, symptoms and other criteria for diagnosing mental disorders.