Content area
Abstract
Abstract
Modafinil is a well-established wakefulness promoter which sustains alertness and performance. However, modafinil's effect on sleep architecture is controversial. Quantifying sleep disturbance on a granular level is difficult, with the literature relying on aggregate measures such as total sleep time and sleep efficiency and traditionally-scored sleep staging. The focus is often on stages N3 and rapid eye movement (REM) due to the high impact associated with their loss. This study investigated the effect of modafinil on sleep architecture, particularly stage N2.
As part of a larger study, 24 individuals were randomly assigned to either a modafinil (200mg) or placebo group. Treatment was administered 30 minutes prior to a 2-hour nap placed after 20 hours of continuous wakefulness. Polysomnography was used to quantify sleep architecture during the nap. Between-groups differences were analyzed using a series of independent t -tests.
Participants in the modafinil group spent significantly more time in N2 than those in the placebo group (53.68 min. vs. 37.86 min., t [22] = 2.24, p = .036), leading to reduced time spent in N3 (52.98 min. vs. 39.97 min., t [22] = 1.62, p = .12) and REM (16.44 min. vs. 8.98 min, t [22] = 1.64, p = .12).
Modafinil significantly increased N2 sleep during a 2-hr nap after 20 hours of continuous wakefulness. N2 is marked by a functional reorganization of consciousness, transitioning from active response to external stimuli during wakefulness to an internal arousal response during N2 sleep which increasingly diminishes as one moves into deeper sleep. Increased time in N2 suggests a repeated failure to complete this transition, remaining in a heightened state of arousal and less restful sleep, possibly leading to cognitive effects downstream masked by modafinil's wakefulness promotion. Our results present a need for studies of modafinil's impact on sleep architecture and subsequent cumulative impacts on cognition.
This research was funded by the Defense Health Program through the Joint Program Committee 5, U.S. Army Medical Research and Materiel Command.