Is It Chronic Fatigue Syndrome or Depression?

Medically Reviewed by Melinda Ratini, MS, DO on November 19, 2022
5 min read

What’s the difference between Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (MF/CFS) and depression? They’re both common, long-term illnesses with many of the same symptoms and some key differences.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (MF/CFS) is also called chronic fatigue syndrome. MF/CFS causes extreme fatigue that has no clear cause.

ME/CFS makes you extremely tired. Even a full night’s sleep doesn’t help. Your fatigue may be worse for a whole day after any type of exercise or activity. You’re too wiped out to do almost anything: take a shower, go to work, cook dinner, do the laundry, or go to the supermarket. You might be unable to get out of bed for any reason. You could have trouble falling asleep or staying asleep.

ME/CFS often causes pain. You could have muscle aches, joint pain, or headaches. It’s also common to have blurry vision or see spots, and to have memory or concentration lapses. You may feel foggy or unable to remember details.

ME/CFS can cause these symptoms, too:

ME/CFS has no known cause. Possible causes include a hormone imbalance, infection with the Epstein-Barr virus (EBV) or other viruses, or an overactive immune system. Your genes might play a role in ME/CFS as well because it often affects people in the same family.

Depression is a common, serious mood problem. It causes deep, ongoing sadness. You may lose interest in activities, socializing, or sex.

Depression often makes you feel sad, empty, guilty, or worthless. You might think about dying or suicide.

Clinical depression can cause physical symptoms too, like fatigue and sleep problems. You might not be able to fall asleep. You may sleep way too much or too little. Or you could wake up way too early. You lack the energy to complete even minor tasks.

Depression can also cause symptoms like:

  • Anxiety
  • Feeling empty
  • Memory or concentration lapses
  • Appetite changes
  • Crying spells
  • Weight loss
  • Sluggish speech or movements
  • Pain with no physical cause, such as back pain or headaches
  • Pacing
  • Hand wringing
  • Digestive problems or belly cramps
  • Restlessness

It’s unclear what causes depression. Physical brain changes, or changes to levels of chemicals called neurotransmitters that play a role in your mood and emotions, may be involved. Hormones often trigger depression. Some women get it after they give birth or enter menopause. Some men also experience depression after having a child. Thyroid problems sometimes cause depression symptoms. Your genes could be linked to depression risk, too.

Sad or unexpected life events often trigger depression. This might be the death of a loved one, a serious or chronic illness, a traumatic experience, or job loss.

ME/CFS and depression can cause fatigue, sleep problems, a lack of energy, pain, digestive problems, headaches, memory lapses, or trouble with concentration.

The way you live with ME/CFS is similar to the way you live with depression. You can try cutting back on activities or avoiding anything that causes stress.

ME/CFS and depression are chronic illnesses. Both conditions may last for years, although your symptoms could be better or worse at times.

ME/CFS and depression are more common in adults, but also affect children and teens. Women are more likely than men to be diagnosed with either ME/CFS or depression.

ME/CFS and depression often affect more than one member of the same family.

ME/CFS may have symptoms that don’t happen with depression, like a frequent sore throat, weakness, and swollen or tender lymph nodes. Pain is more common with CFS than depression.

ME/CFS symptoms like severe fatigue often start or get worse after physical activity, so it could help to cut back on exercise. Depression symptoms sometimes improve after physical activity, so more exercise might make you feel better.

People with ME/CFS often view it as a physical illness. People with depression usually think of their illness as psychological.

Your doctor can diagnose either condition. They’ll start with a complete physical exam and medical history. They’ll ask you about your symptoms, when they started when they happen, and what seems to make them worse or better.

You’ll likely get a diagnosis of ME/CFS if you have sleep problems and at least 6 months of extreme fatigue that doesn’t get better with bed rest and worsens after any physical or mental activity. You’ll also have one of the following symptoms: memory or concentration problems, or dizziness or faintness when you stand up.

You’ll get a diagnosis of depression if you have had certain symptoms for at least 2 weeks. If you’ve had these symptoms for 2 years or more, you’ll get a diagnosis of persistent depression.

Lab tests. Blood or urine tests help rule out other illnesses that cause fatigue, like anemia, diabetes, or thyroid disease. People with ME/CFS may have high levels of certain hormones that could show up on a blood test. A blood test can check for levels of certain inflammatory cells. 

Sleep study. You can be tested to see when your sleep is disturbed. ME/CFS causes more problems during non-REM sleep, or periods of lighter sleep. Depression causes more problems during phases of deep, or REM, sleep.

Psychiatric exam. You might get a mental health exam to diagnose ME/CFS and depression. The doctor will give you a questionnaire designed to screen for depression.

If you have thoughts of suicide, call the Suicide & Crisis Lifeline at 988 or go to the emergency room.