The purpose of the study is to evaluate whether Lemborexant is more effective than placebo in
shortening sleep onset latency in patients with delayed sleep phase syndrome (both type 1 and
type 2). This will be tracked using sleep logs as well as actigraphy.
In this 2-year study, we will examine if Lemborexant administered 5-10 mg nightly taken at
desired bedtime (at least 2 hours prior to self-reported sleep onset habitual time) can
improve the symptoms of Delayed Sleep Phase Syndrome.