Mental health (psychiatric or psychologic) disorders involve disturbances in thinking, emotion, or behavior. Small disturbances in these aspects of life are common, but when such disturbances interfere with daily life, they are considered mental illness or a mental health disorder. The effects of mental illness may be long-lasting or temporary. These disorders are caused by complex interactions between physical, psychologic, social, cultural, and hereditary influences.

Last full review/revision May 2007 by Caroline Carney Doebbeling, MD, MSc