Mood Disorder

Mood can be defined as a pervasive and sustained emotion or feeling tone that influences a person’s behavior and colors his or her perception of being in the world. Disorders of mood—sometimes called affective disorders—make up an important category of psychiatric illness consisting of depressive disorder, bipolar disorder, and other disorders, which are discussed in this section and in the section that follows.


A variety of adjectives are used to describe mood: depressed, sad, empty, melancholic, distressed, irritable, disconsolate, elated, euphoric, manic, gleeful, and many others, all descriptive in nature. Some can be observed by the clinician (e.g., an unhappy visage), and others can be felt only by the patient (e.g., hopelessness). Mood can be labile or alternating rapidly between extremes (e.g., laughing loudly and expansively one moment, tearful and despairing the next). Other signs and symptoms of mood disorders include changes in activity level, cognitive abilities, speech, and vegetative functions (e.g., sleep, appetite, sexual activity, and other biological rhythms). These disorders virtually always result in impaired interpersonal, social, and occupational functioning.

Patients with only major depressive episodes are said to have major depressive disorder or unipolar depression. Patients with both manic and depressive episodes or patients with manic episodes alone are said to have bipolar disorder. The terms “unipolar mania” and “pure mania” are sometimes used for patients who are bipolar but who do not have depressive episodes.

Three additional categories of mood disorders are hypomania, cyclothymia, and dysthymia. Hypomania is an episode of manic symptoms that does not meet the criteria for manic episode. Cyclothymia and dysthymia as disorders that represent less severe forms of bipolar disorder and major depression, respectively.

An almost universal observation, independent of country or culture, is the twofold greater prevalence of major depressive disorder in women than in men. The reasons for the difference are hypothesized to involve hormonal differences, the e􀁐ects of childbirth, psychosocial stressors for women and for men, and behavioral models of learned helplessness. In contrast to major depressive disorder, bipolar I disorder has an equal prevalence among men and women. Manic episodes are more common in men, and depressive episodes are more common in women. When manic episodes occur in women, they are more likely than men to present a mixed picture (e.g., mania and depression). Women also have a higher rate of being rapid cyclers, defined as having four or more manic episodes in a 1-year period.