 Compared to TCAs, SSRIs are generally less sedating because of its high selectivity for serotonin receptors. SSRIs can suppress REM sleep and delay REM latency too, but they increase awakenings and reduce SWS at the same time. One PSG study shown sertraline minimally increases sleep efficiency and reduces nocturnal wakefulness time, which may benefit depressive patients. However, this study compared the sleep architecture before and after 12 weeks of pharmacotherapy, so the tolerance to the disturbance of sleep architecture in antidepressants appears to develop over several weeks of treatment. Sertraline has a greater potency against 5-HT reuptake as well as better selectivity for 5-HT reuptake relative to NE reuptake than any other SSRIs, and the relative selectivity of sertraline for inhabiting 5-HT reuptake relative to DA reuptake is somewhat less than of any other SSRIs. So it has chance to exhibit better effect on sleep architecture in depressive patients. 