Abstract
Introduction: Bipolar disorder commonly has chronobiological disruption and its therapeutic medicines, like lithium has a phase delay effect. In the current study, we compared the effect of quetiapine XR and lithium on circadian rhythm in bipolar depression patients during 8 weeks of trial.
Methods: An open-label, randomized comparison of sleep-activity and depressive symptoms between 8-week quetiapine XR monotherapy and lithium monotherapy for bipolar depression was conducted. Each assessment consisted of Hamilton Depression Rating Scale (HDRS)-17 and self-reported Pittsburgh Sleep Quality Index (PSQI). Actigraphy-measured sleep parameters were assessed and the circadian rhythm were examined using cosinor analysis.
Results: A total of 28 patients(35.9 ± 10.5 years; gender:male12, female16) with bipolar depression were analyzed. Lithium group are 16 patients and quetiapine XR group are 12 patients, there are no significant deference in age and gender. To examine the circadian rhythms, we compared the acrophase in each group. Acrophase of lithium group significantly delayed at weeks1, 2, 4, 6 and 8 compared with baseline (16:22 ± 1:14, 17:20 ± 0:29, 17:33 ± 0:39, 18:27 ± 0:45, 18:42 ± 0:30, 19:04 ± 0:28, p=0.008). Acrophase of quetiapine XR group were advanced than those of lithium group at every weeks (p=0.001), and did not delay in sequence (13:50 ± 0:46, 15:54 ± 0:24, 14:05 ± 1:28, 16:12 ± 0:36, 16:23 ± 0:27, 15:38 ± 0:24) In both groups, HDRS-17 scores were significantly decreased at weeks1, 2, 4, 6 and 8 compared with baseline. In the quetiapine XR group, PSQI scores at weeks1, 2, 4, 6 and 8 was significantly decreased compared with baseline and sleep efficiency (SE) at week 6 and 8 was significantly increased.
Conclusion: Both quetiapine XR and lithium was effective in treating bipolar depression. But lithium was also delay phase, as well as not have to improve the quality of sleep. On the contrary quetiapine XR treatment improved subjective and objective sleep quality in patients with bipolar depression. And quetiapine XR treatment did not affect circadian rhythm.