Impact of Escitalopram on polysomno-graphically recorded sleep and daytime vigilance compared to Amitriptyline and placebo in healthy male subjects

Introduction: We investigated the acute impact of 10mg escitalopram (ESCIT), the s-enantiomer of citalopram, on polysomnographic sleep and daytime vigilance in comparison to 75mg amitriptyline (AMI) and placebo (PLAC) with a double-blind cross-over design. Sleep parameters were recorded by standard polysomnography including a multiple sleep latency test (MSLT). Tricyclic antidepressants (TCA) like AMI generally enhance sleep continuity (SC) (e.g. increased total sleep time (TST), sleep efficiancy (SE) or decreased wake time after sleep onset (WASO) as well as sleep latency (SL)). For both SSRI and TCA an association with increase of periodic limb movements (PLM) during sleep is discussed.

Methods: 12 healthy male subjects underwent 3 periods of 2 consecutive nights of polysomno-graphy in the sleep laboratory separated by at least 7 days. After an adaptation night and 2h before starting night-time recordings for the 2nd night either 10mg ESCIT, 75mg AMI or PLAC was administered double-blind (at 9p.m.). On the following day MSLT was conducted. One subject had to be excluded afterwards because of protocol violation. Each morning subjective sleep parameters were measured by the SF-A and a visual analogue scale. The subscales „subjective sleep quality“, „feeling refreshed in the morning“ and „psycho-somatic symptoms“ of the SF-A were analysed.

Results: Regarding SL and SC there were no remarkable differences after intake of AMI compared to PLAC. Comparing ESCIT with PLAC there was no difference in SL, but SC was significantly impaired (TST, SE, WASO). Both active drugs, AMI (p=0.0011) and ESCIT (p<0.01), significantly increased REM latency and suppressed REMsleep. ESCIT had no effect on PLM or PLM with arousal or on heart rate. However, AMI significantly increased the frequency of PLM with and without arousal (PLM: p=0.0013; PLM with arousal: p<0,05) as well as heart rate in sleep stages 1 and 2. Subjective sleep parameters did not differ significantly between medication and placebo nights. Regarding daytime vigilance as measured by MSLT after the intake of ESCIT wake efficiency (WE) increased significantly. In contrast, AMI led to a pronounced decrease of WE and to a marked reduction in sleep latency during the MSLT.

Conclusion: The evening administration of ESCIT disturbed sleep continuity, however, it had no impact on sleep latency and subjective sleep quality. Additionally, ESCIT improved daytime vigilance in the morning and did not alter nocturnal frequency of PLM or heart rate. AMI, in contrast, increased nocturnal PLM and heart rate. This finding bears importance for the antidepressant treatment of patients with restless legs syndrome or sleep disturbances caused by PLMS. The MSLT data for AMI demonstrated a drastic impairment of daytime vigilance after evening ingestion of AMI. Further analysis will also incorporate spectral analysis of the sleep EEG, to allow a more fine-grained analysis of the effects of AMI and ESCIT on sleep and vigilance.