Commonly prescribed medication for sleep problems raises alarm bells in new study

Amid growing concern about the widespread off-label use of sedative medications for sleep problems, Flinders University researchers have led a world‑first clinical trial examining how a commonly prescribed ‘sleeping pill’ affects sleep, breathing and next‑day performance.

Published in the high‑ranking Annals of the American Thoracic Society, the study found that low‑dose quetiapine (Seroquel) - frequently prescribed off‑label for insomnia - modestly improved sleep quality and reduced obstructive sleep apnoea (OSA) severity, but significantly impaired alertness and driving performance the following day.

Off-label use refers to prescribing a medication for an unapproved purpose. Quetiapine, approved for schizophrenia and bipolar disorder, is increasingly prescribed at low doses for insomnia and anxiety because of its sedative effects.

“There’s a growing belief that low‑dose quetiapine is a relatively harmless way to help people sleep,” says lead author, Cricket Fauska, a PhD candidate for FHMRI Sleep Health at Flinders University.

“Our results show it’s not that simple. Although participants slept longer and woke less overnight, their reaction times were slower, and their simulated driving performance was noticeably worse the next morning.”

The trial focused on people with obstructive sleep apnoea who also struggle to stay asleep - a common but often overlooked combination known as comorbid insomnia and sleep apnoea. While many patients and clinicians assume a better night’s sleep leads to better daytime functioning, the findings suggest this may not hold true when quetiapine is used.

In the randomised, double‑blind, placebo‑controlled study, 15 adults spent two nights in a sleep laboratory - one night after taking 50 milligrams of quetiapine and one after taking a placebo. Full overnight sleep studies were conducted, and the following morning participants completed a driving simulator task and a vigilance test to objectively measure alertness.

Compared with placebo, quetiapine reduced the number of breathing interruptions during sleep and improved sleep efficiency, without worsening oxygen levels. However, it also caused slower reaction times, more lapses in attention and poorer steering control during the driving simulation - markers that are strongly linked to real‑world crash risk.

“What was particularly concerning is that some people didn’t feel especially sleepy the next day, despite performing worse on objective tests,” says Fauska.

“That mismatch between how people feel and how they actually function poses a serious safety risk, especially when it comes to driving.”

Quetiapine is approved to treat conditions such as schizophrenia and bipolar disorder, but it is increasingly prescribed at much lower doses for insomnia, anxiety and general sleep complaints.

Matthew Flinders Professor Danny Eckert, Director of FHMRI Sleep Health and senior author on the paper says the findings raise important questions about current prescribing practices particularly in primary care.

“Around 80 percent of people with OSA are undiagnosed and unaware they have the condition, and to add to this, a key symptom is finding it difficult to stay asleep,” says Professor Eckert.

“Sleep complaints like this are common in general practice, and in Australia around 90 per cent of people who present with insomnia symptoms will leave with a sleeping pill rather than a sleep assessment”.

“Our study shows that while quetiapine can make sleep look better on the surface, it may actually make people less safe the next day.”

The findings also highlight a broader shift in how sleep disorders like OSA are best managed with another new study finding that rather than relying on one‑size‑fits‑all solutions, there is growing evidence that targeting the underlying causes of sleep disruption can improve both treatment effectiveness and patient outcomes.

“Sleep apnoea is a complex condition with different underlying drivers in different people,” says Professor Eckert.

“What we’re learning is that treatment needs to be tailored — using the right approach, or combination of approaches, for the individual rather than defaulting to sedating medications.”

The researchers say better screening for sleep apnoea, increased access to evidence‑based treatments such as cognitive behavioural therapy for insomnia (CBTi), and clear warnings about next‑day impairment are essential.

More than three‑quarters of participants experienced side effects after just a single dose of quetiapine, including grogginess, dizziness and drops in blood pressure. One participant required medical review after a fall.

Although no serious long‑term harm occurred, the researchers say the results underscore the need for caution.

“Our findings suggest quetiapine should not be used as a routine sleep medication in people with known or possible sleep apnoea, particularly when next‑day alertness is critical,” says Professor Eckert.

The research team recommend safer alternatives such as CBTi, alongside care pathways that prioritise sleep apnoea screening before prescribing sedating medications.

Reference:

Cricket Fauska, Tarun Bastiampillai, Georgina Rawson, Barbara Toson, Andrew Vakulin, Robert Adams, Gary Wittert, Kelly A Loffler, Danny J Eckert, Quetiapine modestly improves sleep and breathing but impairs next day performance in people with OSA and difficulty maintaining sleep: A randomized controlled trial, Annals of the American Thoracic Society, 2026;, aaoag092, https://doi.org/10.1093/annalsats/aaoag092