Which of the following is NOT a type of mood disorder?

Anxiety disorder is not classified as a mood disorder, making it the correct choice in this context. While anxiety disorders and mood disorders can both affect a person's emotional state and sometimes co-occur, they represent distinct categories in psychiatric classification.

Mood disorders primarily involve disturbances in a person's emotional state, leading to prolonged periods of sadness, excessive joy, or mood swings. Major depressive disorder involves a significant depressive episode, bipolar disorder features episodes of both mania and depression, and dysthymia (now referred to as persistent depressive disorder) is characterized by a chronic, less severe form of depression lasting for at least two years.

In contrast, anxiety disorders primarily revolve around excessive fear or worry, manifesting through various symptoms such as restlessness, rapid heartbeat, and avoidance behaviors. Examples of anxiety disorders include generalized anxiety disorder, panic disorder, and social anxiety disorder. This distinction is crucial for proper diagnosis and treatment in psychiatric practice.