Acute changes of polysomnography in major depressive disorder patients treated with mirtazapine

Objective To evaluate the acute effects of mirtazapine on sleep polysomnographic variables in patients with major depressive disorder (MDD) using polysomnography (PSG). Methods Twenty-five MDD patients took mirtazapine 15 mg an hour before bedtime during the first three days and then 30 mg during the following four days. Polysomnographic and clinical data were collected at baseline and on the 7th day. Results The scores on the Athens Insomnia Scale (AIS,7.92±3.86,t=10.255,P=0.000), the Hamilton Anxiety Rating Scale (HAMA,6.84±5.57,t=6.137, P=0.000) and the Hamilton Depression Rating Scale (HAMD-17,9.80±4.41,t=12.132,P =0.000) decreased rapidly after a 7-day medication. PSG showed mirtazapine administration significantly increased the total sleep time (402.46±80.75,t=-2.990,P=0.006), the sleep efficiency (76.17%±10.65%,t=-2.750,P=0.011), and the slow wave sleep percentages(19.66%±11.43%,t=3.236, P=0.004) and decreased the wake time after sleep onset (80.38±48.02,t=2.972,P =0.007). However, there was no significant difference in the sleep latency, the number of awakening, the rapid eye movemert (REM) sleep latency, the ratio of REM sleep and the frequency of REM sleep episode. Conclusion Mirtazapine as monotherapy in the treatment of MDD has relieved depressive symptoms rapidly and significantly, increased the total sleep time, the sleep efficiency and the slow wave sleep percentages thus to achieve better sleep quality. Key words: Depressive disorder;  Sleep initiation and maintenace disorders;  Mianserim;  Polysomnography