Poor sleep is often talked about as a single issue. A study published October 7, 2025 in PLOS Biology suggests it is really five, each showing up in the brain in a different way and each carrying its own health signature.
Researchers led by Aurore Perrault of Concordia University in Montreal analyzed data from 770 healthy young adults in the Human Connectome Project, a large US neuroscience dataset. Using a data-driven statistical method, they matched each participant's sleep patterns to 118 measures of mood, cognition, behavior and lifestyle, then compared the groups against resting-state MRI scans of brain network activity.
The result, described in the PLOS Biology paper, was five reproducible sleep-biopsychosocial profiles. "Sleep is made up of many dimensions, not just how long we sleep," Perrault said in a press release about the work.
Most people do not fit neatly into one box. "You're not either one or the other of these profiles. We all express these profiles to a certain degree at some point in our lives," co-author Valeria Kebets of McGill University told Scientific American.
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Which profile might you be?
Profile 1, poor overall sleep. Trouble falling asleep, low satisfaction with rest, frequent disturbances and tired days. In the study this group also reported the most depression, anxiety, somatic complaints and negative emotions like fear and anger. Brain scans showed heightened connectivity between deep subcortical regions and networks that handle movement and attention.
Profile 2, sleep resilience with mental strain. Tired and inattentive during the day, yet reporting no clear problem falling or staying asleep. This group scored high on attention difficulties, ADHD-type symptoms and low conscientiousness, suggesting the brain can carry mental health load without a matching sleep complaint.
Profile 3, regular use of sleep aids. Few daytime complaints and, notably, strong satisfaction with social relationships. On testing, though, this group performed worse on visual episodic memory and on recognizing emotions in others. That echoes long-standing concerns about hypnotic sleep medications and next-day cognition.
Profile 4, short sleepers. People sleeping fewer than six to seven hours a night. They showed slower reaction times and lower accuracy across tasks measuring language, fluid intelligence, emotional processing and social cognition, and scored higher on aggression and lower on agreeableness.
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Profile 5, fragmented sleep. Repeated awakenings, nighttime bathroom trips, breathing issues, pain or temperature problems. This profile was tied to anxiety, intrusive thoughts, substance use including alcohol and cigarettes, and weaker language and working memory.
Why this matters for everyday sleep advice
Roughly 30.5 percent of US adults slept less than seven hours a night in 2024, according to CDC survey data, and the Centers for Disease Control and Prevention recommends at least seven hours for adults aged 18 to 60.
The new work suggests that a blanket "get more sleep" message may miss the point for many people, because short duration is only one of the ways sleep goes wrong.
The study is cross-sectional and observational, which means it can identify patterns but cannot prove that a given sleep profile causes the health or brain differences seen alongside it. The participants were also young and generally healthy, so the profiles need to be tested in older adults and in clinical populations.
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Still, the authors argue that clinicians should ask about sleep in more detail than a single question about hours in bed. Anyone struggling with persistent poor sleep, heavy reliance on sleep medication, or nighttime symptoms such as breathing pauses should raise it with a doctor, since the underlying driver, and the right response, will differ from person to person.
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