Unipolar disorders

Affective disorders A group of psychoses characterised by a pathological and long-lasting disturbance of mood or affect. They include the unipolar disorders (e.g., depression and mania), and bipolar disorders (e.g., manic depression). 

Unipolar disorder An affective disorder characterised by chronic dysphoria. The two contrasting forms of unipolar disorder are major depression and mania. 

Chen, Y. W. and Dilsaver, S. C. Lifetime rates of suicide attempts among subjects with bipolar and unipolar disorders relative to subjects with other Axis I disorders. Biol. Psych. 39 896-899,1996. 

In this chapter we review extant data on the neurobiology of unipolar and bipolar depressive disorders in children and adolescents. A complement to two recent reviews (Kaufman and Ryan, 1999 Kaufman et ah, 2001), this chapter places primary emphasis on those studies in which neuroimaging techniques have been used. Unfortunately, such studies are few and far between. Preclinical models that have guided research on the neurobiology of affective disorders in adults are discussed, and, given the limits in the application of these models to juvenile samples, especially in the case of unipolar disorder, the need for more developmentally focused preclinical work is emphasized. 

The crucial element of both a bipolar and a unipolar disorder is the occurrence of an affective episode. The critical distinction is that bipolar disorder includes hypomanic/manic, depressive, and mixed episodes, whereas a unipolar disorder includes only depressive episodes. The diagnosis proceeds in a stepwise fashion ... 

Black and colleagues (37) studied suicide in subtypes of major mood disorders and compared them with the general population in Iowa. They found an increased risk in all psychiatric groups except for female patients with bipolar mood disorder, which was associated with a lower risk in comparison with unipolar disorders. Seventy-three percent of all suicides occurred during the first few years of follow-up. This trend was particularly pronounced in primary unipolar female patients and bipolar male patients. 

Lithium or lithium-antidepressant combinations, both in bipolar and unipolar disorders... 

TABLE 10-9. Lithium versus placebo for unipolar disorder maintenance treatment... 

It is important to make a conceptual distinction between lithium s relative prophylactic effect for the manic and the depressive phases of a bipolar disorder and, by extension, its ability to prevent recurrent depressions in unipolar disorder. 

An important body of evidence from descriptive, clinical, and genetic sources finds that bipolar disorder is a separate entity from unipolar disorder (i.e., genetically the two variants breed true see also the section Mechanism of Action earlier in this chapter). When we pooled data from several studies that investigated bipolar or unipolar disorders, lithium was more effective than placebo in preventing relapse in bipolar, as well as unipolar, disorders ( Table 10-11 and Table 10-12). 

Mania (affective disturbances) recently has been divided into two functional groups, bipolar and unipolar affective disorders. Bipolar disorders Include both manic and depressive episodes whereas unipolar disorders show only recurrent depressive episodes. Patients with bipolar disorders usually have an early onset of the Illness (20-35 years age) with high incidence of mania and suicide. Some evidence suggests that this condition is hereditary, transmitted through the X-chromosone. On the other hand, onset of unipolar disorders usually occurs at a later age (30-45) and hereditary association is less well defined. 

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