Conventional antidepressants start to improve the sleep patterns of patients 3-4 weeks following initiation of treatment; however, most of their effects are on REMS and their effects on NREMS are less significant (58).
Temporal characteristics of delta activity during NREM sleep in depressed outpatients and healthy adults: group and sex effects.
Additionally, the duration of NREMS was increased significantly from 438.17 [+ or -] 21.2 to 501.36 [+ or -] 14.23 min (1 = 5.102, df = 5, P = 0.0038, Figure 2(c)(C1)).
They were reported to have an increase in the NREMS delta power in the Per gene mutation mice after sleep deprivation, compared with wide-type mice [15, 16].
(a) indicates the typical EEG and EMG recording, respectively, for wake, NREMS, and REMS times.
The result was confirmed by dramatic changes in the PSG (including decreased REMS and increased Stage III NREMS) one month after starting the atypical antipsychotic medication.
Studies report that clozapine, olanzapine, risperidone, paliperidone, and quetiapine improve sleep quality through their antagonistic effects on several receptors in the central nervous system, including the 5-HT (5-HT1 and 5HT2), dopamine (D1 and D2), histamine (H1), and noradrenaline ([alpha]l and [alpha]2) receptors [8,9] In 1990, Sharpley and colleagues  discovered a dose-response relationship between the dosage of medications that antagonize 5-HT2C receptors and increases in Stage III NREMS (i.e., slow-wave sleep).