Which of the following is NOT classified as a mood disorder?

Generalized Anxiety Disorder is the correct answer because it is classified as an anxiety disorder, not a mood disorder. Mood disorders primarily involve disturbances in how a person feels, leading to prolonged periods of intense emotional states that can affect a person's overall functioning.

Major Depressive Disorder, Bipolar Disorder I, and Dysthymia are all classified as mood disorders. Major Depressive Disorder is characterized by a persistent feeling of sadness and loss of interest, while Bipolar Disorder I involves mood swings from extreme highs (mania) to lows (depression). Dysthymia, now more commonly referred to as Persistent Depressive Disorder, involves long-term depression that can be less severe than Major Depressive Disorder but lasts for years.

In contrast, Generalized Anxiety Disorder encompasses excessive, uncontrollable worry about various aspects of life, which is a defining characteristic of anxiety disorders rather than mood disorders.