What are mood disorders?

Mood disorders include major depressive disorder, dysthymic disorder, and bipolar disorder:

Approximately 20.9 million American adults, or about 9.5 percent of the U.S. population age 18 and older in a given year, have a mood disorder The median age of onset for mood disorders is 30 years Depressive disorders often co-occur with anxiety disorders and substance abuse

This answer is based on source information from the National Institute of Mental Health.

Mark Moronell, MD
Cardiology (Cardiovascular Disease)
Mood disorders such as bipolar disorder encompass a large group of psychiatric disorders. The term "mood disorders" is used by psychiatrists, psychologists and other mental health experts today to refer to sustained emotional states and not merely to the external  mood, or affective, expression of someone's present emotional state. Mood disorders are syndromes (rather than discrete diseases), consisting of a cluster of signs and symptoms that are sustained over a period of weeks to months, and represent a marked departure from a person's habitual functioning. They tend to recur often in periodic or cyclical fashion.
Marked by sometimes dramatic shifts in energy, behavior, mood and thought, mood disorders affect and even warp an individual's outlook and perception of reality. Like other physical diseases, these disorders can be treated with medications, lifestyle changes, psychotherapy and other therapies. Healthcare professionals and patient advocates have been working hard to help the general public understand that mood disorders have nothing to do with character flaws or weaknesses. Rather, they are treatable chemical and biological anomalies that respond to many safe and affordable therapies.

Mood disorders those disorders that have as their central feature a disturbance in mood.

Major depression is characterized by one or more major depressive episodes, which are defined as experiencing two or more weeks of (1) depressed mood and/or (2) loss of interest or pleasure in daily activities. To be diagnosed with major depression, a person must experience one or both of these symptoms and a total of five or more depressive symptoms.

Mild-to-moderate depression is called dysthymia, which involves depressed mood for a protracted period of time -- at least two years -- but without major depressive episodes. To be diagnosed with mild-to-moderate depression, a person must exhibit depressed mood plus at least two other mood-related symptoms.

Bipolar disorder (manic depression) is cyclical. Unlike depression, which is characterized only by lows and is therefore sometimes called unipolar depression, bipolar disorder involves mood swings from very low (depression) to inappropriately high (mania). Three types of bipolar disorder are distinguished. Bipolar I disorder involves the most radical mood swings -- from major depression to extreme mania. Bipolar II disorder involves deep lows (major depression) cycling with moderate mania (hypomania). Cyclothymia is a cycling mood disorder characterized by mood alternating between mild-to-moderate depression (dysthymia) and moderate mania (hypomania).

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.