Bipolar disorders

The bipolar disorders are bipolar 1 disorder, bipolar II disorder, and cyclothymia.

Bipolar I Disorder

Bipolar I disorder is the most serious of the bipolar disorders and is diagnosed after at least one episode of mania (Table 2-3). Patients with bipolar I disorder typically also have major depressive episodes in the course of their lives.

Epidemiology

The lifetime prevalence is 0.4% to 1.6% and the male-female ratio is equal. There are no racial variations in incidence.

Etiology

Genetic and familial studies reveal that bipolar I disorder is associated with increased bipolar I, bipolar II, and major depressive disorders in first-degree relatives. X linkage has been demonstrated in some studies but remains controversial. Mania can be precipitated by psychosocial stressors, and there is evidence that sleep/wake cycle perturbations may predispose a person to mania.

Clinical Manifestations

History and Mental Status Examination
Bipolar J disorder is defined by the occurrence of mania (or a mixed episode). A single manic episode is sufficient to meet diagnostic requirements; most patients, however, have recurrent episodes of mania typically intermixed with depressive episodes. The criteria for a manic episode are outlined in Table 2-3.

The first episode of mania usually occurs in the early 20s. Manic episodes are typically briefer than depressive episodes. The transition between mania and depression occurs without an intervening period ofeuthymia in abouttwo of three patients (Fig. 2-2A).
Lifetime suicide rates range from 10% to 15%.

Differential Diagnosis

Mania may be induced by antidepressant treatment, including antidepressant medications, psychostimulants, ECT, and phototherapy. When this occurs, the patient is diagnosed with substance-induced mood disorder, not bipolar disorder. Mood disorder due to a general medical condition is the other major differential consideration. Schizo affective disorder, borderline personality disorder, and depression with agitation are also considerations.

Figure 2-2. Bipolar mood disorders. (A) bipolar I disorder, (B) bipolar II disorder, (C) cyclothymic disorder.

Management