A prominent and persistent disturbance in mood characterized by either or both of the following: depressed mood or markedly diminished interest or pleasure in all, or almost all, activities; and elevated, expansive, or irritable mood. The clinical and laboratory findings must support that either the symptoms developed during, or within a month of, substance intoxication or withdrawal, or that the medication (i.e., substance) is causally related to the disturbance. The condition cannot be better accounted for by a mood disorder that is not substance induced. The disturbance does not occur exclusively during the course of a delirium. The symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.