There are many different categories of mental disorder, and many different facets of human behavior and personality that can become disordered.[10][11][12][13][14]

Anxiety or fear that interferes with normal functioning may be classified as an anxiety disorder.[15] Commonly recognized categories include specific phobias, generalized anxiety disorder, social anxiety disorder, panic disorder, agoraphobia, obsessive-compulsive disorder and post-traumatic stress disorder.

Other affective (emotion/mood) processes can also become disordered. Mood disorder involving unusually intense and sustained sadness, melancholia, or despair is known as major depression (also known as unipolar or clinical depression). Milder but still prolonged depression can be diagnosed as dysthymia. Bipolar disorder (also known as manic depression) involves abnormally "high" or pressured mood states, known as mania or hypomania, alternating with normal or depressed mood. The extent to which unipolar and bipolar mood phenomena represent distinct categories of disorder, or mix and merge along a dimension or spectrum of mood, is subject to some scientific debate.[16]

Patterns of belief, language use and perception of reality can become disordered (e.g., delusions, thought disorder, hallucinations). Psychotic disorders in this domain include schizophrenia, and delusional disorder. Schizoaffective disorder is a category used for individuals showing aspects of both schizophrenia and affective disorders. Schizotypy is a category used for individuals showing some of the characteristics associated with schizophrenia but without meeting cutoff criteria.

Personality—the fundamental characteristics of a person that influence thoughts and behaviors across situations and time—may be considered disordered if judged to be abnormally rigid and maladaptive. Although treated separately by some, the