Quetiapine Improved Sleep but Impaired Driving Performance in New Trial

A widely used antipsychotic that many doctors quietly prescribe as a sleep aid may carry hidden risks for people with sleep apnea, new research suggests. The small clinical trial found that quetiapine, known by the brand name Seroquel, impaired next-day alertness and driving performance despite improving sleep.

Quetiapine is officially approved to treat conditions such as schizophrenia and bipolar disorder, but low doses are increasingly prescribed off-label for insomnia. Researchers from Flinders University in Australia warn that this practice could be dangerous, particularly for patients with undiagnosed obstructive sleep apnea, a condition estimated to affect 1 billion people worldwide.

What the new study found

The study involved 15 adults with obstructive sleep apnea who also had difficulty maintaining sleep. In a randomized crossover design, participants took either a low dose of quetiapine or a placebo on separate nights, allowing researchers to compare the two conditions within the same individuals.

Overnight, quetiapine produced the effect many patients and doctors hope for: participants slept longer and woke up less frequently. However, the following day they performed significantly worse on objective measures of alertness and simulated driving than they did under the placebo condition.

On a standard 10-minute psychomotor vigilance test, reaction times were slower after quetiapine, and lapses in attention increased from a median of 2 with placebo to 10 with the drug. In a driving simulator, volunteers drifted 33 percent farther from the center of their lane and nearly doubled their crash rate, although the small sample size meant this latter finding did not reach strong statistical significance.

A dangerous gap between feeling and function

Researchers say one of the most concerning findings was the mismatch between how participants felt and how they actually performed. Some did not report feeling particularly sleepy, yet their reaction times and driving control were clearly impaired.

This disconnect may increase real-world risks, especially for people who drive, operate machinery, or perform safety-critical work the morning after taking quetiapine. Unlike medications with well-known sedative warnings, low-dose quetiapine may create a false sense of security because patients view it as a simple sleep aid.

The authors stress that their trial was limited to a single night of treatment and a small group of participants, so the long-term effects of repeated low-dose use remain unclear. However, they argue that even short-term impairment is concerning given how frequently the medication is prescribed off-label for insomnia.

Overlap of insomnia and sleep apnea

Obstructive sleep apnea occurs when the upper airway repeatedly collapses during sleep, causing pauses in breathing, snoring, drops in blood oxygen levels, and fragmented sleep. It is strongly associated with daytime sleepiness, cardiovascular disease, and metabolic disorders.

Insomnia and sleep apnea often coexist, and as many as 80 percent of people with sleep apnea are thought to be undiagnosed. Patients may primarily complain of poor sleep or frequent awakenings, leading clinicians to focus on insomnia and prescribe sedating medications without recognizing the underlying breathing disorder.

In such cases, a medication like quetiapine may appear effective because it reduces awakenings while quietly worsening next-day alertness and potentially masking symptoms that would otherwise prompt evaluation for sleep apnea.

Calls for more cautious prescribing

The Flinders University team concludes that quetiapine should not be used as a routine sleep medication in people with known or suspected sleep apnea, particularly when next-day performance is important. They call for closer oversight of its off-label use and for clinicians to screen more carefully for sleep-disordered breathing before prescribing it.

Experts note that treatment for obstructive sleep apnea is moving away from a one-size-fits-all approach. Available options now include continuous positive airway pressure (CPAP), oral appliances, positional therapy, weight-loss strategies, nerve-stimulation implants, and, more recently, experimental drug therapies.

The authors argue that rather than defaulting to sedating medications, clinicians should pursue tailored combinations of these approaches. Larger trials are now needed to evaluate different quetiapine doses over longer periods and to better understand which patients, if any, can safely use it as a sleep aid.

The research was published in the Annals of the American Thoracic Society and adds to growing evidence that psychiatric medications used off-label for insomnia may carry underappreciated safety risks, especially in people with unrecognized sleep apnea.