Breaking the Cycle of Fatigue: Mass General Brigham Clinical Trial Finds Sunosi Successfully Treats Shift Work Disorder in Early Morning Employees

While midnight oil has long been the literary and cultural symbol for late-night labor, contemporary economic reality dictates a different dawn. Far more people report to work during the deep twilight hours of the early morning than pull traditional overnight graveyard shifts. Yet, despite being the most prevalent form of non-standard work scheduling, early-morning labor has historically been overlooked in clinical sleep research. Millions of individuals who begin their days while the rest of the world sleeps suffer quietly from severe, chronic fatigue tied directly to their occupational routines. This persistent exhaustion is not merely a matter of wanting an extra hour in bed; it is a clinical condition known as shift work disorder, characterized by profound daytime sleepiness, cognitive deficits, and disrupted circadian rhythms.

Recent findings published in the medical journal NEJM Evidence offer a beacon of hope for this massive, underserved workforce. A pioneering clinical trial led by researchers at Mass General Brigham has demonstrated that the wake-promoting pharmaceutical agent solriamfetol, commercially known as Sunosi, can significantly enhance alertness, cognitive function, and overall job performance in early-morning shift workers. By targeting the profound biological mismatch between demanding work hours and the human body’s natural internal clock, this new research marks a watershed moment in occupational health, potentially transforming how modern society manages the hidden human costs of round-the-clock infrastructure.

The Anatomy of Early-Morning Exhaustion and the Circadian Conflict

To understand the severity of shift work disorder among early risers, one must first examine the intricate mechanics of human biology. The human body operates on a roughly 24-hour internal biological cycle known as the circadian rhythm, which is primarily regulated by the suprachiasmatic nucleus in the brain. This master clock dictates physiological functions, hormone release, body temperature fluctuations, and sleep-wake cycles largely in response to environmental cues, most notably natural light and darkness.

For individuals who begin their shifts between 3:00 a.m. and 7:00 a.m., their professional obligations force them to wake up and perform complex cognitive or physical tasks precisely during a window when their brains are biologically programmed for deep, restorative sleep. This creates a severe physiological contradiction. Even workers who maintain high levels of internal motivation and professional dedication find themselves fighting an overwhelming neurological tide.

According to Dr. Kirsi-Marja Zitting, an investigator with the Division of Sleep and Circadian Medicine in the Mass General Brigham Department of Medicine and the first author of the study, these individuals face a relentless "double burden." Not only do they experience excessive, debilitating sleepiness during their working hours, but they also struggle to achieve sufficient, high-quality sleep when they finally have the opportunity to rest. Their daytime sleep is frequently fragmented, as it runs counter to the natural circadian drive for daytime alertness and must contend with external environmental disruptions such as daytime daylight and ambient neighborhood noise.

Quantifying the Modern Shift Work Landscape

The societal reliance on non-standard work hours is more pervasive than many realize. Labor statistics and public health data indicate that approximately one in four workers in industrialized economies operates outside the conventional Monday-through-Friday, 9-to-5 paradigm. This vast demographic includes healthcare professionals, transportation workers, emergency responders, sanitation crews, logistics and warehousing personnel, and hospitality staff—the essential cogs that keep urban infrastructure functioning before the sun rises.

Crucially, many individuals caught in this cycle do not self-identify as traditional "shift workers." Because their shifts start in the early pre-dawn hours rather than midnight, they often rationalize their fatigue as a mere lifestyle inconvenience or simply view their routine as starting the day earlier than normal. However, neurologically and physiologically, their bodies experience the exact same circadian disruption as overnight workers.

The consequences of this pervasive sleep deprivation extend far beyond individual discomfort. Chronic shift work disorder is heavily implicated in a cascade of negative health and safety outcomes. Studies consistently link the condition to reduced mental sharpness, slower reaction times, impaired decision-making, and lowered workplace productivity. More alarmingly, the profound lapses in concentration associated with untreated sleep disorders dramatically elevate the risk of motor vehicle accidents during the morning commute, as well as severe, preventable workplace injuries.

Furthermore, long-term epidemiological data suggests that chronic circadian misalignment is associated with an increased incidence of metabolic syndrome, cardiovascular disease, gastrointestinal disorders, and mental health struggles such as anxiety and depression. Despite these alarming stakes, therapeutic interventions have historically lagged behind the scale of the problem. Until this recent Mass General Brigham trial, pharmaceutical clinical trials for shift work disorder had focused almost exclusively on overnight or rotating shift workers, leaving the massive early-morning workforce entirely without targeted medical solutions.

Evaluating Solriamfetol: A Targeted Therapeutic Approach

Historically, clinicians managing shift work disorder have relied on wakefulness-promoting agents such as modafinil. While effective for some populations, these traditional medications have primarily been studied in the context of overnight schedules and carry distinct pharmacological limitations, including the potential to interfere with subsequent sleep episodes when workers attempt to rest later in the day.

Solriamfetol presented researchers with a compelling alternative. The medication is a dual-acting dopamine and norepinephrine reuptake inhibitor that has already secured regulatory approval for the treatment of excessive daytime sleepiness in patients suffering from obstructive sleep apnea and narcolepsy. Pharmacologically, solriamfetol is designed to promote sustained wakefulness and mental alertness over extended periods without causing the erratic crash or prolonged sleep disruption associated with older stimulants.

To test its efficacy specifically within the early-morning shift worker demographic, researchers designed a rigorous, randomized, placebo-controlled clinical trial. The study enrolled 78 participants who had been formally diagnosed with shift work disorder and whose work schedules began in the early-morning hours. Over a four-week period, these participants were assigned to take either solriamfetol or an inactive placebo on their scheduled workdays.

Methodology and Clinical Outcomes of the Trial

The trial structure incorporated both objective physiological assessments and subjective quality-of-life metrics. Researchers evaluated participants’ capacity to maintain wakefulness in a controlled, low-stimulation laboratory environment during hours that precisely mirrored their typical early-morning work schedules. Additionally, participants maintained daily functional logs and met regularly with clinical staff to report on their subjective experiences, alertness levels, and capacity to manage daily professional and personal responsibilities.

The results after four weeks of treatment were definitive and statistically significant. Participants who received solriamfetol exhibited marked improvements in their objective ability to stay awake during simulated work hours compared to the placebo group. Subjective reporting mirrored these physiological findings: both the patients themselves and the attending clinicians noted substantial enhancements in overall functional capacity, enhanced on-the-job performance, and a vastly improved ability to execute complex daily tasks without succumbing to debilitating exhaustion.

Dr. Charles A. Czeisler, PhD, MD, the senior author of the study and chief and senior physician of the Division of Sleep and Circadian Medicine at Mass General Brigham, emphasized the real-world significance of the data. The improvements observed were not merely incremental statistical changes, but clinically meaningful gains that allowed workers to remain fully awake and alert throughout an entire eight-hour shift. This sustained vigilance holds profound implications for occupational safety, professional productivity, and the fundamental quality of life for millions of employees.

Chronology of Research and Institutional Support

The journey toward recognizing and treating early-morning shift work disorder has been decades in the making within the field of sleep medicine. Dr. Czeisler and his colleagues at Mass General Brigham have long advocated for a broader medical understanding of circadian biology and its direct impact on occupational health.

The specific clinical trial under discussion—officially registered under identifier NCT04788953—was initiated following years of epidemiological observation highlighting the vulnerability of early-morning labor forces. Formally launched in March 2021, the trial represented a collaborative academic and industry effort. The research was funded through a combination of institutional support from the Brigham and Women’s Hospital Center for Clinical Investigation, alongside industry sponsorship from Jazz Pharmaceuticals and Axsome Therapeutics.

The publication of the findings in NEJM Evidence in late 2023 and early 2024 served as a watershed moment, formally placing early-morning shift work disorder on the map as a legitimate, treatable medical condition requiring specialized clinical intervention.

Broader Implications and Future Horizons for Occupational Health

The implications of the Mass General Brigham trial extend far beyond the immediate pharmacological success of solriamfetol. By scientifically validating the reality of early-morning shift work disorder and demonstrating that it can be safely and effectively managed, the study challenges employers, healthcare providers, and policymakers to rethink how they approach the health and safety of the non-standard workforce.

Modern industrial economies rely heavily on continuous operations. From the nurses arriving at hospital wards at 5:00 a.m. to the logistical personnel orchestrating supply chains before dawn, the societal cost of ignoring worker fatigue is unsustainable. When workers are chronically sleep-deprived, error rates soar, economic productivity drops, and public safety is compromised on highways and in workplaces alike.

However, researchers and public health advocates caution that pharmaceutical interventions are only one piece of a much larger puzzle. While solriamfetol provides a critical pharmacological tool to help bridge the biological gap, mitigating the risks of shift work disorder ultimately requires a multifaceted approach. This includes smarter scheduling practices that respect circadian principles, such as limiting consecutive early shifts, providing adequate recovery time between work blocks, and educating both workers and employers about the physiological realities of sleep debt.

Moreover, the research team at Mass General Brigham emphasizes that the current trial represents an initial step. Because the study was limited to a four-week duration and focused on otherwise healthy adults, further investigation is mandatory to establish the long-term safety and efficacy profile of solriamfetol for chronic use in this population.

Recognizing these horizons, the research group is already expanding its scope. The team is actively enrolling participants for a subsequent clinical trial designed to evaluate the effects of solriamfetol in overnight shift workers. Data from this upcoming trial could provide the comprehensive clinical evidence necessary to support broader regulatory approvals for the treatment of shift work disorder across all scheduling spectrums.

In addition to lead contributors Dr. Zitting and senior author Dr. Czeisler, the Mass General Brigham research team included Katherine R. Gilmore, Brandon J. Lockyer, Wei Wang, Nicolas C. Issa, Stuart F. Quan, Jonathan S. Williams, and Jeanne F. Duffy, alongside independent researcher Eileen B. Leary. Their collective work signals a paradigm shift in sleep medicine—one that acknowledges the invisible biological toll paid by the millions of essential workers who wake up in the dark so that society can function in the light.