A widely prescribed antipsychotic medication commonly used to treat sleep disorders may significantly impair driving ability the morning after use, according to new research from Australia. The study found that quetiapine, marketed as Seroquel, reduced sleep apnea symptoms but left participants with dangerously slowed reaction times behind the wheel. Most concerning, one in four people taking the medication failed to recognize their level of impairment.
The research, conducted by Flinders University in Adelaide, examined 15 adults diagnosed with obstructive sleep apnea who also struggled with maintaining sleep throughout the night. Each participant completed two overnight sleep studies approximately one week apart, taking 50mg of quetiapine on one night and a placebo on the other. The medication is FDA-approved for schizophrenia, bipolar disorder and depression, but doctors frequently prescribe it off-label at lower doses for insomnia, anxiety and other sleep-related conditions.
Sleep quality improved but driving performance declined sharply
Participants who took quetiapine experienced notable improvements in sleep metrics compared to those on placebo. Total sleep time increased by more than 40 minutes, while wakefulness during the night decreased by 45%. Apnea-related breathing events dropped from 27 to 20 per hour, indicating measurable relief from the primary sleep disorder symptoms. Researchers monitored breathing patterns, brain activity, oxygen levels and leg movements throughout the night to track these improvements.
However, the medication’s benefits came with significant morning-after consequences. Within 30 minutes of waking, participants completed a driving simulator test and a 10-minute reaction time assessment. Those who had taken quetiapine the previous night showed more than triple the number of attention lapses compared to the placebo group. They also swerved out of their lane more frequently during the simulated driving scenarios, demonstrating compromised vehicle control.
Most users felt sleepy but many misjudged impairment severity
Eleven out of 15 participants reported feeling sleepier the morning after taking quetiapine, acknowledging some level of grogginess. Yet researchers identified a troubling pattern: roughly one in four people did not recognize the true extent of their impairment. This disconnect between perceived and actual ability raises serious safety concerns, as these individuals might confidently get behind the wheel or operate machinery without realizing their reaction times had slowed considerably.
- More than triple the attention lapses during reaction tests
- Increased lane departure frequency in driving simulations
- One in four users unable to recognize impairment level
- Eleven out of 15 participants reported morning sleepiness
- Side effects included nausea and sudden blood pressure drops
The study also documented other mild to moderate side effects experienced by participants. Nausea and restless legs affected some users, while one in three people taking quetiapine experienced orthostatic hypotension, a sudden drop in blood pressure upon standing. These additional symptoms compound the medication’s potential safety risks for daily activities.
Experts recommend caution pending larger studies
The research team acknowledged several limitations to their findings, including the small sample size of just 15 participants and the single-night evaluation period. The laboratory setting may not fully reflect how people use quetiapine in real-world conditions at home. Researchers emphasized that larger, longer-term studies are necessary before making definitive recommendations about prescribing quetiapine specifically for sleep apnea and insomnia treatment.
Until additional research confirms these findings, the team recommends that people avoid driving or performing safety-critical tasks for at least 9.5 hours after taking quetiapine. Ashley Curtis, director of the Cognition, Aging, Sleep and Health Lab at the University of South Florida, noted that certain hypnotic medications show significant differences in how men and women metabolize them. Women generally process these drugs more slowly, which can influence both effectiveness and the risk of next-day side effects.
Behavioral therapy remains important component of treatment
Curtis, who was not involved in the study, stressed that future research should carefully examine whether newer sleep medications demonstrate similar sex-specific metabolism patterns to ensure optimal dosing recommendations. The impact on next-day cognitive function particularly warrants investigation among older adults, a population already vulnerable to side effects from taking multiple medications simultaneously. Understanding potential trade-offs between sleep benefits and daytime functioning becomes essential for this demographic.
Insomnia often results from learned behavioral and cognitive factors that persist over time, according to Curtis. Even when medications prove effective in the short term, behavioral interventions such as cognitive behavioral therapy for insomnia remain an important component of long-term management. Chelsie Rohrscheib, head sleep expert at Wesper, a New York-based sleep analysis company, agreed that patients shouldn’t panic over these findings. However, she recommended that anyone taking quetiapine for sleep, especially those with sleep apnea or who wake feeling groggy, should consult their doctor about whether the benefits outweigh the risks and explore alternative treatment options.
