A medication often used as a quick fix for sleepless nights may come with a troubling trade-off: better-looking sleep, poorer next-day performance.
A new clinical trial led by sleep health researchers at Flinders University has raised fresh concern about low-dose quetiapine, sold under the brand name Seroquel, when prescribed off-label for insomnia.
The drug is approved for conditions such as schizophrenia and bipolar disorder. In everyday practice in many parts of the world, though, it is increasingly given at much lower doses to people who cannot sleep, often because of its strong sedating effect.
The findings, published in the Annals of the American Thoracic Society, suggest the picture is more complicated than many patients, and some prescribers, may realise. In adults with obstructive sleep apnoea who also had trouble staying asleep, a single 50 mg dose of quetiapine helped participants sleep longer, wake less often, and experience fewer breathing interruptions during the night.
Yet the following morning, the same participants reacted more slowly, had more lapses in attention, and drove less safely in a simulator.
Sleep medicines are usually judged by what happens overnight. Did the person fall asleep? Did they stay asleep? Did they feel rested? This study asks a sharper question. What happens the next morning, when that person gets behind the wheel, walks downstairs, goes to work, cares for children, or makes decisions that require alertness?
The answer, at least in this small trial, was uncomfortable.
Researchers tested 15 adults in a randomised, double-blind, placebo-controlled study. Each participant spent two separate nights in a sleep laboratory. On one night, they received 50 mg of quetiapine. On the other, they received a placebo. Neither the participants nor the study team assessing outcomes knew which treatment had been given on which night.
During the night, full sleep studies measured breathing, oxygen levels, sleep stages, and awakenings. The next morning, participants completed a driving simulator task plus a vigilance test designed to detect subtle reductions in attention. These are not casual measures. Slower reaction times, steering problems, and attention lapses are established warning signs for real-world crash risk.
Compared with placebo, quetiapine modestly improved sleep efficiency. Participants spent more of their time in bed asleep. They also had fewer breathing interruptions linked to obstructive sleep apnoea, known as OSA. Importantly, oxygen levels did not appear to worsen overnight.
At first glance, that may sound reassuring.
The morning results told a different story. Participants showed slower responses, poorer steering control, and more lapses in attention after taking quetiapine. Some did not feel particularly sleepy, despite performing worse on objective tests. That gap between perceived alertness and actual function is one of the most important findings in the trial. People may believe they are safe to drive, even when their reaction time and attention have been impaired.
This is where the study becomes especially relevant to routine medical care. Off-label prescribing is common in many areas of medicine. It is not unlawful, nor automatically inappropriate. It means a medication is being used for a purpose, dose, or patient group not specifically approved by regulators. Clinicians may do this when evidence, experience, or patient needs support it.
The issue with quetiapine for insomnia is that its use has expanded widely despite lingering questions about risk, benefit, and next-day safety. It is not licensed as a standard sleeping tablet. It was developed as an antipsychotic. Even at low doses, it affects brain chemistry in ways that can cause sedation, dizziness, blood pressure changes, and cognitive slowing.
OSA is common. It is also often undiagnosed. The Flinders University researchers note that around 80% of people with the condition may not know they have it. Many present not with dramatic choking episodes, but with broken sleep, tiredness, snoring, morning fog, or difficulty staying asleep. In general practice, those symptoms can be labelled as insomnia, stress, anxiety, ageing, or poor sleep habits.
According to the researchers, in Australia, about 90% of people who present with insomnia symptoms leave with a sleeping pill rather than undergoing a formal sleep evaluation. Many health systems face the same pressure such as short appointments, long waits for sleep services, distressed patients, and a strong desire for quick relief.
Comorbid insomnia and sleep apnoea, sometimes called COMISA, is a particularly challenging combination. People struggle to sleep, yet their breathing also repeatedly collapses or narrows during sleep. Treating only the insomnia may leave the breathing disorder untouched. Treating only the sleep apnoea may not resolve the sleeplessness. Sedating the patient may make sleep appear smoother while leaving next-day functioning worse.
The finding that quetiapine reduced breathing interruptions may surprise some readers. Many sedatives are viewed with caution in sleep apnoea because they can relax airway muscles, reduce arousal responses, or worsen oxygen drops in some patients. This study did not show worsening oxygen levels after a single low dose. It showed a modest improvement in breathing indices. Still, the improvement did not translate into safer next-day performance.
In plain terms, the drug made some sleep measurements look better. It made morning function look worse.
That distinction is vital for patients. A medication can increase sleep duration without improving the quality of waking life. It can reduce awakenings while impairing alertness. It can create the impression of a good night, then leave someone slower, less steady, less responsive.
The side-effect findings also deserve attention. More than three-quarters of participants reported side effects after just one dose. These included grogginess, dizziness, and drops in blood pressure. One participant needed medical review after a fall. No serious long-term harm was reported in the study, but the events reinforce why “low dose” should not be confused with “low risk”.
The study was small, so it should not be read as the final word on quetiapine, insomnia, or sleep apnoea. Fifteen participants cannot answer every clinical question. The trial measured short-term effects after a single 50 mg dose in a specific group. Adults with OSA plus difficulty maintaining sleep. It does not prove the same effects would occur in every patient, every dose, or every setting.
Yet small mechanistic trials can be powerful when they measure outcomes that matter. This one used overnight sleep studies, objective vigilance testing, and simulated driving. It also studied a real-world prescribing problem. Many patients taking low-dose quetiapine for sleep may have undiagnosed OSA. Many may drive the next morning. Many may underestimate their impairment.
That is why the research is likely to influence conversations about prescribing, screening, and safer treatment pathways.
The researchers argue that quetiapine should not be used as a routine sleep medication in people with known or possible sleep apnoea, especially when next-day alertness is important. That includes drivers, shift workers, machinery operators, carers, clinicians, pilots, emergency workers, and anyone whose morning performance affects safety.
The message is not that people should abruptly stop prescribed medication. Stopping quetiapine suddenly can be inappropriate, particularly for those taking it for approved psychiatric conditions. The safer message is more practical. People using quetiapine for sleep should discuss risks, benefits, alternatives, and possible sleep apnoea screening with a qualified health professional.
The study also strengthens the case for cognitive behavioural therapy for insomnia, usually known as CBTi. This is not generic sleep hygiene advice. CBTi is a structured, evidence-based treatment that targets the behaviours, thoughts, and patterns that maintain insomnia. It can be delivered face to face, in groups, through telehealth, or through validated digital programmes. For many people with chronic insomnia, it is recommended as a first-line treatment.
Access remains a barrier. Pills are often easier to obtain than therapy. Waiting lists can be long. Digital options vary in quality. Some patients need support for anxiety, pain, trauma, menopause symptoms, medications, alcohol use, irregular schedules, or other factors that disrupt sleep. Still, the principle is clear. Treating insomnia should not begin and end with sedation.
Screening for sleep apnoea is another key step. Warning signs include loud snoring, witnessed pauses in breathing, gasping during sleep, morning headaches, high blood pressure, daytime sleepiness, waking unrefreshed, and repeated night-time awakenings. Not everyone with OSA fits the stereotype. It can affect women, younger adults, people without obesity, and those whose main complaint is insomnia rather than sleepiness.
For clinicians, the latest trial offers a timely prompt. Before prescribing a sedating medication for insomnia, ask whether sleep apnoea could be present. Consider whether the patient drives early, works in safety-critical roles, has falls risk, takes other sedating medicines, drinks alcohol, or has low blood pressure.
For patients, the takeaway is equally direct. If a sleeping pill leaves you groggy, dizzy, slow, unsteady, or foggy the next day, do not dismiss it as normal. If you snore, wake gasping, repeatedly wake through the night, or feel unrefreshed despite enough hours in bed, ask about sleep apnoea assessment. If you are taking quetiapine only for sleep, ask whether safer, evidence-based options might suit you better.
This new trial does not minimise that suffering. It adds a necessary caution. A quieter night is not always a safer morning.
Sleep treatment should help people live better after they wake up. That is the standard that matters.
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