A mental disorder, also called a mental illness, psychological disorder or psychiatric disorder, is mental or behavioral pattern that causes either suffering or a poor ability to function in ordinary life. Such features may be persistent, relapsing and remitting, or occur as a single episode. Many disorders have been described, with signs and symptoms that vary widely between specific disorders. Typically, social norms and religious or cultural beliefs are excluded.[citation needed] The causes of mental disorders are often unclear. Theories may incorporate findings from a range of fields. Mental disorders are usually defined by a combination of how a person feels, acts, thinks or perceives. This may be associated with particular regions or functions of the brain, often in a social context. A mental disorder is one aspect of mental health.
