Mood disorders in multiple sclerosis: diagnosis and treatment. 
Emotional disturbances are common in MS and consist of disturbances of mood and disturbances of affect.  The important mood disorders are major depressive disorder, dysthymic disorder, bipolar disorder, panic disorder, and generalized anxiety disorder.  Their relationship to MS is multi-factorial and complex, and the extent to which they are direct consequences of the disease process or psychological reactions to it remains unclear.  Whatever their cause, however, the symptoms of mood disorders in people with MS are no different from the symptoms of mood disorders in people without MS, and respond just as well to standard treatments.  The disorders of affect are euphoria, pathological laughing and weeping, and other frontal lobe syndromes.  These disorders result from demyelination, are some of the most characteristic symptoms of MS, and have the same implications for treatment as do other aspects of the disease.  Mood and affective disturbances can cause enormous pain and suffering and lead to significant disruption of family, work, and social life.  Physicians who can identify, diagnose, treat, and manage mood and affective disturbances effectively and who can help their patients and family members acknowledge these difficulties, talk about them, and accept psychiatric consultation and treatment can have a dramatic impact on the quality of their lives.  This paper outlines the symptoms and diagnostic criteria for mood disorders and affective disturbances, reviews current treatment options, summarizes data from epidemiologic and pathophysiological studies, and suggests areas for future research.