The Connection Between Sleep and Depression

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Sleep helps your body function. It isn’t just about staying alert — getting good sleep also affects your heart, immune, and mental health.

A lack of sleep and fatigue are closely linked to depression. They share a bidirectional relationship, meaning they can affect each other. They also share symptoms and warning signs.

So, which one is the cause? And which is the symptom?

Here’s more about how sleep and depression can connect and when to see a doctor for help.

What Is Fatigue?

Fatigue is a lack of energy or motivation that persists for weeks or longer.

After a poor night’s sleep, you expect to feel tired. But fatigue is much more serious. It disrupts your daily life, making it difficult to go to work or school, or find the interest or energy to do anything.

According to the American Academy of Sleep Medicine, stress, anxiety, and depression are major sleep disruptors for adults in the United States. But fatigue has several other causes, including:

• Anemia or iron deficiency.
• Chronic pain.
• Drugs or alcohol.
• Medication side effects.
• Other health conditions (such as cancer, heart disease, lung disease, kidney disease, or diabetes).
• Overactive or underactive thyroid.
• Sleep disorders.

What Is Depression?

Depression is one of the most common mental illnesses, affecting millions of people.

People with depression often feel sad, guilty, worthless, tired, irritable, or angry, combined with a loss of interest or pleasure in activities. Even daily tasks like eating or working become difficult.

Symptoms of depression include disrupted sleep and fatigue, or feeling very tired and low in energy. But there are many other symptoms or warning signs, including:

• Anger or irritability.
• Changes in appetite or weight.
• Feelings of excessive guilt, low self-worth, and hopelessness.
• Loss of interest in activities.
• Physical pain.
• Poor concentration and focus.
• Thoughts of dying or suicide.

Symptoms of depression can last for weeks, months, or even years.

What Is the Connection Between Sleep and Depression?

Symptoms and risk factors connect sleep and depression. For example, fatigue is a common symptom of depression and can help diagnose it. While sleep disorders, like insomnia, can be a risk factor for depression.

But there isn’t always a link between sleep and depression. You can experience fatigue but not feel depressed. And you can have depression without fatigue symptoms.

Both may also be separate symptoms of a completely different health condition or side effects of a medication.

Is Lack of Sleep a Symptom of Depression?

Lack of sleep, as well as fatigue, low energy, and tiredness, can all be symptoms of depression.

Depression can make it difficult to fall asleep. This is especially when feelings of sadness, hopelessness, and other depressive thoughts take over when you try to sleep.

Often, experiencing depression and tiredness throughout the day leads to trying to nap, which can further impact nighttime sleep. Disrupting your routines and sleep schedule can also lead to sleep loss and fatigue.

Some people with depression find they’re not sleeping enough, but not everyone. Others sleep more and are constantly tired and disconnected from things they used to love.

Can a lack of sleep cause depression?

A lack of sleep is a risk factor for depression. According to the American Academy of Sleep Medicine, experts tie not getting enough sleep to a higher risk of depression.

After a night of tossing and turning, your body doesn’t function well. Lack of sleep inhibits your brain’s ability to manage emotions and impairs thinking. This can intensify or put you at a higher risk for mental illnesses.

When to Talk to My Doctor About Lack of Sleep and Depression

It is important to reach out to your doctor if you have sleep issues and fatigue. Even if you know the reason, such as you’re trying to adapt to a new work or school schedule.

Healthy sleep is key to your physical health, and this proactive step may help protect your mental and emotional health, too.

Also seek help if you’re experiencing depression along with a lack of sleep, especially if symptoms last for weeks or affect your daily life. Your primary care provider (PCP) can recommend at-home and lifestyle strategies, therapies, and medication to help improve sleep and treat depression.

Consider tracking your sleep to share examples of your sleep schedule and routine with your health team. If your lack of sleep persists, a sleep study can also help identify sleep disorders, such as sleep apnea, that require additional treatment.

You might also track your other symptoms, including how you feel. Knowing all of your symptoms will give your doctor a bigger picture of what’s going on. It may help them determine whether fatigue is a symptom of something more, like depression.

Given the link between sleep and depression, improving one area may improve the other. But your doctor needs to identify the root cause of your lack of sleep to address the right issue.