Science Made Simple: Your Depression Might Have a Hidden Physical Cause You Can Actually Fix

EVIDENCE TO ACTION | Science Made Simple | The State of Women Institute

By Dr. Odessa Lacsina, Executive Director, The State of Women Institute

If you are struggling with depression, anxiety, or mood disorders and treatments are not working, there is something your doctor might be missing.

A study published in JAMA Network Open in December 2025 followed more than 30,000 people for nearly three years and found that people at high risk for sleep apnea had 40% higher odds of poor mental health — both at the time of the study and at the three-year follow-up.

The connection between sleep apnea and mental health is not new. What this study adds is scale, duration, and a finding that should change how we approach treatment-resistant depression and anxiety, particularly in women.

What Is Sleep Apnea?

Obstructive sleep apnea (OSA) causes repeated breathing interruptions during sleep. The airway narrows or collapses, cutting off oxygen — and a person may partially wake hundreds of times a night without knowing it.

The result is fragmented sleep, oxygen drops, stress responses, and chronic inflammation. And here is the part that surprises most people: up to 90% of people with sleep apnea don't know they have it. Nearly 936 million adults worldwide are affected, but most remain undiagnosed — often dismissed as simply snoring too much or feeling tired.

The Mental Health Connection

Lead researcher Dr. Tetyana Kendzerska and her team at Ottawa Hospital Research Institute found that sleep apnea significantly increases the risk of depression, mood disorders, anxiety disorders, and psychological distress — with depression showing the strongest link.¹

Among participants who began the study without any mental health conditions, those at high risk for sleep apnea had 20% higher odds of developing mental health problems by the three-year follow-up.

In other words, sleep apnea does not simply coexist with mental health issues. The evidence suggests it may actively cause or worsen them over time.

Why This Especially Matters for Women

Women are significantly underdiagnosed with sleep apnea because the condition presents differently across sexes.

Men typically experience: Loud snoring, gasping, obvious breathing pauses.

Women often experience: Insomnia, fatigue, morning headaches, depression, and anxiety — symptoms that are frequently dismissed as stress or hormonal fluctuation rather than investigated as signs of a sleep disorder.

If you are a woman being treated for depression or anxiety without improvement, it is worth asking your doctor specifically about sleep apnea screening.

The STOP Questionnaire: A Simple Self-Screen

The STOP questionnaire is a validated clinical screening tool. If you answer yes to two or more of the following four questions, you may be at high risk for sleep apnea and should speak with your doctor about a sleep study:

• S — Snore: Do you snore loudly?

• T — Tired: Do you often feel tired, fatigued, or sleepy during the day?

• O — Observed: Has anyone observed you stop breathing during sleep?

• P — Pressure: Do you have, or are you being treated for, high blood pressure?

Two or more yes answers is a reason to follow up. A sleep study can now be done at home in many cases — no overnight lab visit required.

Why the Connection Makes Sense

When sleep apnea goes untreated, the body undergoes a nightly cascade of stress. Intermittent oxygen drops deprive the brain of what it needs to function. Sleep fragmentation prevents the restorative deep sleep during which the brain processes emotions and consolidates memories. Chronic inflammation alters brain chemistry. Cortisol surges through the night, keeping the stress response in sustained overdrive. And the neurotransmitters that regulate mood — serotonin and dopamine — are disrupted.

This is not simply a matter of being tired. The brain is being stressed, repeatedly, night after night, with no recovery.

What You Can Do

Start with the STOP screening above. If you score two or more, talk to your doctor about a sleep study. Many studies can now be completed at home.

Treatment typically begins with CPAP therapy — a mask that keeps the airway open during sleep — though alternatives exist for mild to moderate cases, including oral appliances, positional therapy, and in some cases, surgical options. The first step is getting an accurate diagnosis.

If you are struggling with depression, anxiety, or mood symptoms — especially if current treatments have not been effective — sleep apnea is worth ruling out. It is a real, physical condition with real mental health consequences. And it is treatable.

Have you or someone you know been screened for sleep apnea?

Source

¹ Kendzerska, T., et al. "Obstructive Sleep Apnea Risk and Mental Health Conditions Among Older Canadian Adults." JAMA Network Open, December 26, 2025. Ottawa Hospital Research Institute. https://doi.org/10.1001/jamanetworkopen.2025.49137

Study population: 30,097 adults ages 45–85, followed for a median of 2.9 years.

Dr. Odessa Lacsina is the Executive Director of The State of Women Institute, a 501(c)(3) nonprofit working across three health equity pillars: Mental Health & Wellness, Maternal Health Equity, and Preventive Wellness.

To learn more or support women's health leadership, visit thestateofwomen.org or follow @thestateofwomen.