The study was led by Kirsi-Marja Zitting from Brigham and Women’s Hospital in Boston, Massachusetts, and colleagues. Shift work disorder is characterized by excessive sleepiness and impaired alertness caused by misalignment between work schedules and the body’s circadian rhythm. While treatments for night-shift–related sleepiness have been studied extensively, early-morning shift workers—whose schedules often begin between 3 a.m. and 7 a.m.—remain understudied.
To address this gap, investigators conducted a randomized, double-blind, placebo-controlled trial to evaluate the efficacy of solriamfetol, a selective dopamine and norepinephrine reuptake inhibitor. The study enrolled 78 adults with early-morning SWD who reported excessive sleepiness related to their work schedules. Participants were randomly assigned to receive either solriamfetol or a placebo for four weeks.
The primary outcome was objective sleepiness, assessed using the Maintenance of Wakefulness Test (MWT), which measures how long an individual can stay awake in a quiet, low-stimulation environment. Longer sleep latency on the test indicates improved alertness. Secondary outcomes included subjective sleepiness measured by the Karolinska Sleepiness Scale, as well as clinician- and patient-reported assessments of overall clinical change.
The key findings were as follows:
- After four weeks of treatment, participants receiving solriamfetol showed significantly better objective wakefulness compared with those given placebo.
- Solriamfetol-treated patients demonstrated an average increase of 9.4 minutes in sleep latency on the Maintenance of Wakefulness Test, indicating reduced sleepiness, and this difference was statistically significant.
- Subjective sleepiness also improved, with patients in the solriamfetol group reporting lower scores on the Karolinska Sleepiness Scale than those in the placebo group.
- Clinician assessments indicated a higher likelihood of clinical improvement among participants treated with solriamfetol compared with placebo.
- Patient-reported outcomes similarly showed that individuals receiving solriamfetol were more likely to perceive meaningful improvement in their condition.
- Adverse events were reported in both treatment groups, with 55% of participants receiving solriamfetol and 63% of those receiving placebo experiencing at least one event.
- The most commonly reported side effects associated with solriamfetol were headache and nausea.
- No unexpected safety issues or serious safety concerns were observed during the study period.
The authors concluded that solriamfetol significantly improved both objective and subjective measures of sleepiness in early-morning shift workers with SWD. They noted that these results expand the evidence base for treating shift work disorder beyond night-shift populations and highlight the need for further research tailored to different work schedules.
While the study was limited by its relatively small sample size and short duration, the findings suggest that solriamfetol may represent an effective therapeutic option for managing excessive sleepiness in early-morning shift workers, a group that often struggles with chronic fatigue and impaired daytime functioning.
Reference:
Zitting KM, Gilmore KR, Lockyer BJ, Leary EB, Wang W, Issa NC, Quan SF, Williams JS, Duffy JF, Czeisler CA. Solriamfetol for Excessive Sleepiness in Early-Morning Shift Work Disorder. NEJM Evid. 2026 Feb;5(2):EVIDoa2500190. doi: 10.1056/EVIDoa2500190. Epub 2026 Jan 27. PMID: 41590992.
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