One in nine adults reported weekly nightmares in 2021

How common are frequent nightmares? Most figures come from single countries, each asking the question in its own way. A new short report in the Journal of Sleep Research asked the same questions in 16 countries at once, and the answer was higher than many textbooks suggest: in 2021, about one adult in nine said they had nightmares every week.^[1]

What the study did

Courtney Bolstad and colleagues used data from the International COVID-19 Sleep Study, a collaboration that ran one online survey between May and November 2021 in Austria, Brazil, Bulgaria, Canada, Croatia, Finland, France, Germany, Hong Kong, Israel, Italy, Japan, Norway, Portugal, Sweden and the United States. In all, 15,854 adults aged 18 to 99 took part; 69.9% were women.

People were asked how often they had nightmares and remembered dreams “currently”, and how often they had them before the pandemic, “say, in 2019”. Anyone answering once a week or more counted as frequent. The paper appeared online in April 2025 and in the journal’s first issue of 2026.^[1]

What it found

• Nightmares. 11.0% reported weekly nightmares in 2021, against 6.9% when they looked back to 2019.
• Dream recall. 54.0% remembered dreams at least weekly in 2021, and 51.1% for 2019.
• Countries. In 2021, Brazil had the highest rate of weekly nightmares (19.0%) and Israel the lowest (3.4%).
• Age and gender. Adults aged 18 to 34 reported weekly nightmares most often (12.3% in 2021). Women reported slightly more than men in 2021 (11.1% and 10.7%); for 2019 the pattern reversed.

The most interesting pattern was sleep length. Dream recall rose steadily the longer people slept. Nightmares followed a U-shape: most common in people who slept under six hours or over nine, least common in between.^[1]

The authors suspect insomnia may explain the link with short sleep, and more REM sleep the link with long sleep. They did not test either idea in this report.

Why it is higher than older figures

Earlier surveys, mostly in single European countries, put weekly nightmares at between 0.9% and 6.8%.^[1] A representative German survey published in 2010 found 2.4%, but it counted only bad dreams that woke people up.^[2] This survey simply asked about “nightmares”, so some of the difference is probably about definitions. The authors also suggest the pandemic, rising rates of mental health problems, and less stigma about reporting nightmares.

What it does not show

• It was taken during the pandemic. The figures may not hold in calmer times.
• 2019 was remembered, not measured. People recalled their sleep two years later, so the authors did not test the change statistically.
• Samples differed between countries. The United States surveyed undergraduate students; Italy tried to include more people with long COVID; Germany also recruited from a sleep clinic. For this reason the authors did not compare countries statistically.
• Many causes were not measured. The report did not look at stress, trauma, mental health, other sleep problems or COVID-19 infection.

What this means for you

If you have nightmares every week, you are far from alone. Weekly nightmares are not the same as nightmare disorder, which also involves real distress or trouble during the day and affects around 4% of adults; it is treatable, and imagery rehearsal is the approach sleep medicine recommends.^[3] Read more about when bad dreams become a condition and how imagery rehearsal works. If the pandemic years changed your dreams, we wrote about what 2020 taught dream researchers. And if the headlines linking weekly nightmares with early death worried you, we read them carefully.