Idiopathic Hypersomnia and Chronic Fatigue Syndrome

Medically Reviewed by Neha Pathak, MD on March 22, 2024
3 min read

At first glance, idiopathic hypersomnia (IH) and chronic fatigue syndrome (CFS) look alike. They both involve daytime tiredness and unrefreshing sleep. But IH and CFS, now sometimes called myalgic encephalomyelitis (ME), are completely different medical conditions. Though some symptoms may overlap, there are signature features that set these two apart.

IH and CFS can both negatively affect your quality of life. They cause similar symptoms, like:

  • Daytime tiredness even if you get enough sleep
  • Unrefreshing sleep
  • Dizziness when you stand up
  • Headaches
  • Problems with concentration, memory, or thinking
  • Feeling too hot or too cold
  • Anxiety or depression

IH and CFS seem to be more different than they are similar. There are key differences in symptoms, causes, treatment, and the number of people that have these conditions.

Symptoms. One key difference is that IH mainly causes sleepiness, while CFS triggers fatigue. 

There are other symptoms that differ between IH and CFS, too. For instance, people with IH often have sleep inertia, which is feeling groggy or confused when you wake up. You may not be able to move when you wake up. Or, you could see or hear things that aren’t there when you wake up or fall asleep. People with IH also tend to sleep for long periods at night. These aren’t typical symptoms of CFS.

People with CFS face their own distinctive set of issues. One is that fatigue and pain often worsen after physical or mental effort. While IH is primarily a sleep condition, CFS can cause symptoms that affect the whole body, like: 

  • Muscle or joint pain
  • Nausea or vomiting
  • Heart palpitations
  • Breathing changes
  • Bladder or bowel problems
  • Fever

Causes. Doctors don’t know exactly what causes either IH or CFS. But they do think different processes in your body might trigger each condition.

IH is considered a sleep disorder of the brain. It’s likely caused by a disturbance in how your brain controls its sleep cycles. 

CFS isn’t a sleep disorder, though sleep problems can be a symptom. Instead, CFS is a serious, long-term illness that affects many of your body systems. Doctors refer to it as a “complex” condition. 

Treatments. CFS and IH may require different treatments. 

Typical treatment for IH involves medications and lifestyle changes to help manage symptoms. These may include things like keeping a regular sleep schedule, getting regular exercise, and limiting your use of alcohol and caffeine. 

Therapies for CFS are usually more varied. Doctors may suggest medications and lifestyle changes along with things like relaxation methods such as meditation or deep breathing. Talk therapy can also help by showing you how to recognize behaviors that make you feel tired and unable to complete activities.  

How common they are. IH is considered a rare disorder. Experts think that it affects about 20 to 50 of every 1 million people.  

CFS seems to be more common. It’s thought to affect up to 2.5 million people in the United States.

The short answer is yes, you can have IH and CFS at the same time. If this happens, you’re said to have comorbid conditions. But keep in mind that IH and CFS are often misdiagnosed or missed altogether. 

Some studies have found up to 91% of people with CFS are undiagnosed or misdiagnosed with other disorders, like depression. When it comes to IH, research shows around 61% of people are misdiagnosed with other conditions like anxiety, depression, narcolepsy, or sleep apnea.

Still, research shows that about 56% of people with CFS also have some type of sleep disorder. So you could end up with both conditions.

Idiopathic hypersomnia and chronic fatigue syndrome are two debilitating illnesses that can affect your daily life. And neither one has a known cure. While there are some similarities between these two conditions, there are plenty of things that set them apart. Talk to your doctor if you think you might have either of these disorders. The right treatments can help you feel better and live a more productive life.