Effects of quetiapine on sleep architecture in patients with unipolar or bipolar depression

OBJECTIVE To determine the effect of adjunctive quetiapine therapy on the sleep architecture of patients with bipolar or unipolar depression. METHODS This is a prospective, single-blind, repeated measures polysomnographic study. Sleep architecture was analyzed by overnight polysomnography, and subjective sleep quality was measured using the Pittsburgh Sleep Quality Index. The Hamilton Rating Scale for Depression, Montgomery Asberg Depression Rating Scale, Young Mania Rating Scale, and Clinical Global Impression-Severity Scale were employed to quantify changes in illness severity with adjunctive quetiapine treatment. Polysomnographs and clinical measures were administered at baseline, after 2-4 days of treatment, and after 21-28 days of quetiapine treatment. The average dose of quetiapine was 155 mg, ranging from 100-200 mg. RESULTS Adjunctive quetiapine therapy did not significantly alter sleep efficiency, sleep continuity, or Pittsburgh Sleep Quality Index scores. Respiratory Disturbance Index and percentage of total time in rapid eye movement (REM) sleep significantly decreased and the percentage of total time in non-REM sleep, and duration of Stage 2 and non-REM sleep significantly increased after 2-4 days of quetiapine treatment. Illness severity significantly decreased over time. CONCLUSIONS Adjunctive quetiapine treatment alters sleep architecture in patients with major depressive disorder or bipolar disorder, which may partially explain its early antidepressant properties. Changes in sleep architecture are more robust and significant within two to four days of starting treatment.