The term mood describes a pervasive and sustained emotional state that may affect all aspects of an individual’s life and perceptions. Mood disorders are pathologically elevated or depressed disturbances of mood, and include full or partial episodes of depression or mania. A mood episode (for example, major depression) is a cluster of symptoms that occur together for a discrete period of time.
A major depressive episode involves a depression in mood with an accompanying loss of pleasure or indifference to most activities, most of the time for at least 2 weeks. These deviations from normal mood may include significant changes in energy, sleep patterns, concentration, and weight. Symptoms may include psychomotor agitation or retardation, persistent feelings of worthlessness or inappropriate guilt, or recurrent thoughts of death or suicide. The diagnosis of major depression requires evidence of one or more major depressive episodes occurring without clearly being related to another psychiatric, alcohol or other drug (AOD) use, or medical disorder. Major depression is subclassified as major depressive disorder, single episode and recurrent. There are nine symptoms of a major depressive episode listed in the DSM-IV draft, and diagnosis of this disorder requires at least five of them to be present for 2 weeks.
Dysthymia is a chronic mood disturbance characterized by a loss of interest or pleasure in most activities of daily life but not meeting the full criteria for a major depressive episode. The diagnosis of dysthymia requires mild to moderate mood depression most of the time for a duration of at least 2 years.
A manic episode is a discrete period (at least 1 week) of persistently elevated, euphoric, irritable, or expansive mood. Symptoms may include hyperactivity, grandiosity, flight of ideas, talkativeness, a decreased need for sleep, and distractibility. Manic episodes, often having a rapid onset and symptom progression over a few days, generally impair occupational or social functioning, and may require hospitalization to prevent harm to self or others. In an extreme form, people with mania frequently have psychotic hallucinations or delusions. This form of mania may be difficult to differentiate from schizophrenia or stimulant intoxication.
A hypomanic episode is a period (weeks or months) of pathologically elevated mood that resembles but is less severe than a manic episode. Hypomanic episodes are not severe enough to cause marked impairment in social or occupational functioning or to require hospitalization.
Bipolar disorder is diagnosed upon evidence of one or more manic episodes, often in an individual with a history of one or more major depressive episodes. Bipolar disorder is subclassified as manic, depressed, or mixed, depending upon the clinical features of the current or most recent episodes. Major depressive or manic episodes may be followed by a brief episode of the other.
Cyclothymia can be described as a mild form of bipolar disorder, but with more frequent and chronic mood variability. Cyclothymia includes multiple hypomanic episodes and periods of depressed mood insufficient to meet the criteria for either a manic or a major depressive episode. The revised third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R) states that for a diagnosis of cyclothymia to be made, there must be a 2-year period during which the patient is never without hypomanic or dysthymic symptoms for more than 2 months.
Substance-induced mood disorder is described in the DSM-IV according to the following criteria:
- A prominent and persistent disturbance in mood characterized by either (or both) of the following:
1) depressed mood or markedly diminished interest or pleasure in all, or almost all, activities,
2) elevated, expansive, or irritable mood.
- There is evidence from the history, physical examination, or laboratory findings of substance intoxication or withdrawal, and the symptoms in criterion A developed during, or within a month of, significant substance intoxication or withdrawal.
- The disturbance is not better accounted for by a mood disorder that is not substance induced. Evidence that the symptoms are better accounted for by a mood disorder that is not substance induced might include: the symptoms precede the onset of the substance abuse or dependence; they persist for a substantial period of time (e.g., about a month) after the cessation of acute withdrawal or severe intoxication; they are substantially in excess of what would be expected given the character, duration, or amount of the substance used; or there is other evidence suggesting the existence of an independent non-substance-induced mood disorder (e.g., a history of recurrent non-substance-related major depressive episodes) .
- The symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.
- The disturbance does not occur exclusively during the course of delirium.
Substance-induced mood disorder can be specified as having 1) manic features, 2) depressive features, or 3) mixed features. Also, it can be described as having an onset during intoxication or withdrawal. For most of the major mental illnesses, the DSM-IV draft includes the alternative of a substance-induced disorder within that diagnosis.