with bipolar disorder (9), sleep disturbance was the most common symptom of mania, reported by more than three quarters of patients, and the sixth most common symptom of bipolar depression, reported by one fourth of the number of patients. Insomnia is also a significant and common problem among patients with bipolar disorder even when they are euthymic. In a recent study (10), ten percent of euthymic patients with bipolar disorder reported a significant sleep disturbance including impaired sleep efficiency, increased anxiety about poor sleep, and decreased daytime activity levels due to lack of sleep. Lastly, it has been suggested that the disruption of the sleep-wake cycle may be a causative factor in the development of bipolar disorder, postulating that these patients have a genetic diathesis for circadian rhythm instability. These authors propose (11,12) that psychosocial stressors may cause disrupted routine and sleep, which consequently disrupts already vulnerable circadian rhythms and may trigger a mood episode. Sleep quality is one of the most objective measures of improvement or deterioration in bipolar disorder and may serve as either a signal, or a trigger of manic, or hypomanic episodes (13,14). Lack of sleep may cause a switch from depression to mania in as many as 6% of vulnerable patients (15). Therefore, insomnia and disruptive sleep are a consequence of a mood episode, may serve as a signal of an oncoming mood episode, or be a cause of an elevated mood episode. Disrupted sleep and circadian rhythms may also have a causative role in the development of bipolar disorder itself. It is critical, therefore, for the clinician to monitor sleep-wake cycles and intervene quickly if sleep is disrupted.
How long has the patient had difficulty with sleep?
When in the night does the problem occur?
difficulty falling asleep?
awakening in the middle of the night (sleep continuity disturbance)?
early morning awakening?
function (16). If there is suspicion of a sleep-related breathing disorder, periodic leg movements, or nocturnal seizure disorder, polysomnography, a nocturnal electroencephalograph (EEG), or electromyography (EMG) may be helpful. These tests, however, are not routinely performed in the patient with elevated mood unless there are signs of these disorders. As with most patients with elevated mood who are to be placed on medication, a battery of laboratory screening tests including routine electrolytes, chemistries, blood urea nitrogen (BUN), creatine, liver function, thyroid-stimulating hormone (TSH), and complete blood count (CBC) should be obtained.
TABLE 11.1 Factors causing short-term or transient insomnia in hypomanic patients
TABLE 11.2 Pittsburgh sleep quality index