Sleep apnea’s hidden link to depression and mental health problems

You can live for years with obstructive sleep apnea and never know it. The condition repeatedly narrows your upper airway during sleep. That can break up your rest, strain your body, and lower oxygen levels overnight. Researchers have long suspected that this kind of disrupted sleep can affect your mental health, too.

To test that idea at scale, research teams from the University of Ottawa and the Ottawa Hospital Research Institute, working with the Canadian Longitudinal Study on Aging looked at whether people at high risk for obstructive sleep apnea also faced higher odds of anxiety, depression, and psychological distress over time. The analysis was reviewed through ethics approvals that included the Hamilton Integrated Research Ethics Board, using CLSA data from a national, community-based cohort of middle-aged and older adults.

The results point to a consistent pattern. When you show signs that place you at high risk for sleep apnea, you are more likely to report poor mental health at the same time. You are also more likely to report new mental health problems a few years later.

Mental health conditions are among the leading contributors to global disease burden. Anxiety and depressive disorders are among the most common. People living with mental health conditions face higher risks of cardiometabolic disease, unemployment, homelessness, disability, and hospitalizations. Mental disorders also cost about $1 trillion a year worldwide in lost productivity.

Sleep apnea sits in the middle of that picture in a way many people miss. Obstructive sleep apnea is common and widely underdiagnosed. It involves repeated breathing interruptions or severe narrowing that fragments your sleep. That can trigger stress responses in your body and cause intermittent drops in oxygen.

Estimates suggest obstructive sleep apnea affects hundreds of millions of adults ages 30 to 69 worldwide, and many cases go undetected. Yet sleep apnea is treatable. Evidence-based, cost-effective therapies can improve symptoms and lower long-term health risks.

That makes the unanswered question especially important. If untreated sleep apnea worsens mental health, then diagnosing it earlier could help protect both your body and your mind.

The researchers ran a secondary analysis of the Canadian Longitudinal Study on Aging. The CLSA tracks biological, medical, cognitive, psychological, social, lifestyle, and economic factors in middle-aged and older adults. For this analysis, the team used the Baseline Comprehensive Cohort, collected from 2011 to 2015, and Follow-up 1, collected from 2015 to 2018.

At baseline, the study included 30,097 people ages 45 to 85. At follow-up, it included 27,765 people. The median follow-up period was 2.9 years.

The primary exposure was “high risk” of obstructive sleep apnea using a validated screening tool called the STOP questionnaire. You are classified as high risk when you report at least two of these: snoring, daytime sleepiness, witnessed apnea, or hypertension. Hypertension was defined using measured blood pressure or a self-reported diagnosis or medication use.

The researchers also tested a simpler secondary measure based on one question: “Has anyone ever observed you stop breathing in your sleep?” That “witnessed apnea” question can be more specific, but it misses many cases.

"To measure mental health outcomes, our team used a composite definition of “poor mental health.” It counted if you met any of these markers: a high score on a short depression scale, a high score on a psychological distress scale, a self-reported physician diagnosis, or self-reported antidepressant use. We also looked separately at physician-diagnosed anxiety disorder, mood disorder, and clinical depression," Tetyana Kendzerska, lead researcher from the Inflammation and Chronic Disease Program at the Ottawa Hospital Research Institute, told The Brighter Side of News.

"Because many factors shape both sleep and mental health, we adjusted for a wide set of possible confounders. Those included demographics, lifestyle measures, other sleep symptoms, and medical conditions," she continued.

The sample had a substantial share of people at high risk for sleep apnea. At baseline, 7,066 of 30,097 participants, or 23.5%, were at high risk. At follow-up, 7,493 of 27,765 participants, or 27.0%, were at high risk. Witnessed apnea was reported by 14.1% at baseline and 16.8% at follow-up.

Poor mental health was also common. At baseline, 10,334 participants, or 34.3%, met the composite outcome. At follow-up, 8,851 participants, or 31.9%, met it. Among those who did not meet the composite outcome at baseline, 6.9% met it at follow-up.

After adjustment for confounders, being at high risk of sleep apnea was linked with higher odds of the composite poor mental health outcome at both time points. At baseline, the odds ratio was 1.39. At follow-up, it was 1.40. That works out to roughly a 40% higher odds, on average, compared with those at low risk.

The longitudinal results mattered most for cause-and-effect questions. Among people without the composite mental health outcome at baseline, high risk of sleep apnea was associated with higher odds of developing the outcome by follow-up. The odds ratio was 1.20, or about 20% higher odds.

The pattern held when the team used the witnessed apnea question. Witnessed apnea was associated with increased odds in cross-sectional, longitudinal, and repeated-measures analyses. In repeated-measures models that accounted for within-person change over time, the association between high sleep apnea risk and the composite mental health outcome remained significant.

Across the separate outcomes, the strongest links appeared with mood disorder and clinical depression. The associations with psychological distress and anxiety disorder were present, too, but tended to be more modest.

The study also explored which characteristics, among people already at high risk of sleep apnea, were associated with developing new mental health conditions.

Among 3,213 participants at high risk for sleep apnea who did not report mental health conditions at baseline, 11.2% developed the composite outcome at follow-up. Factors associated with higher odds included female sex, lower household income, lower life satisfaction, poorer self-rated general health, and other sleep problems. Those other sleep problems included restless legs, acting out dreams, and insomnia symptoms.

In a broader repeated-measures analysis of people at high risk for sleep apnea, the risk profile expanded. Younger age, living in an apartment rather than a house, not drinking alcohol, lower BMI, respiratory problems, traumatic brain injury, pain severity, more medications, and several sleep symptoms were linked with worsening mental health over time.

Pain stood out as a practical concern. Pain, mental health, and sleep apnea can reinforce each other. Anxiety and depression can amplify pain. Chronic pain can raise mental health risk. Sleep apnea has also been linked with pain severity in other research, and treatment may help some patients.

The study does not prove that sleep apnea causes mental health conditions. It is observational. But the researchers describe several plausible pathways.

When your oxygen dips repeatedly, it can affect brain systems that regulate mood. When your sleep fragments night after night, your stress and hormone systems can shift. Inflammation may also play a role, since sleep apnea has been associated with elevated inflammatory markers, and inflammation has been linked with depression in other work.

Sleep apnea also clusters with cardiometabolic conditions. Those health burdens can increase mental distress. In older adults, cardiovascular health is also a known risk factor for depression, which may help explain why depression-related outcomes showed some of the strongest associations.

If you are an older adult who snores, feels unusually tired during the day, has high blood pressure, or has a partner who notices breathing pauses, this study supports taking those signs seriously. Screening for sleep apnea could become a more routine part of mental health care, especially for people with depressive symptoms or mood disorders.

For clinicians and health systems, the findings argue for more integrated care. Sleep evaluations that also include brief mental health screening could help identify people at higher risk sooner. The reverse approach also matters. If you are treated for anxiety or depression, and you have symptoms of sleep apnea, identifying and treating sleep apnea could remove a chronic stressor that keeps symptoms from improving.

For researchers, the work helps define who to study next. The results point to subgroups that may benefit from targeted prevention efforts, including people with other sleep disorders, chronic pain, respiratory problems, traumatic brain injury, and high medication burden.

Future studies can also test whether sleep apnea treatment changes mental health trajectories, since treatment data were not available here.

Research findings are available online in the journal JAMA Psychiatry.

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