Catathrenia, or nocturnal groaning, is a relatively rare and undocumented parasomnia, in which the subject groans during their sleep – often quite loudly. This disorder is long lasting, and seems to occur nightly in most people. It can occur during any stage of sleep, but seems to happen with the most frequency during REM or deep sleep. It can come and go during the night, and restless sleep with a lot of tossing and turning may actually ward it off, as it’s been documented that subjects who move around a lot experience breaks in the groaning after shifts in position. This also may tie into the contention that it occurs mostly during deep sleep.

Contrary to snoring which occurs during inhalation, groaning occurs during exhalation, and one groan can last as long as 30 seconds. The groans are usually succeeded by a snort or sigh at the end. Groaning usually comes and goes in stretches, with any one stretch lasting as long as an hour.

Groaning is not related in any way to sleep-talking. It has also shown no connection to general breathing problems or sleep related breathing problems, any abnormal brain activity or mental disorders, or any other sleep related disorders in general. What causes the groaning in people is still a relative mystery.

The groaning bears no connection to any mental anguish or dream state the person may be in, a common misconception. Though people in these states have been known to make small groaning noises, they are not related to catathrenia. Other sleep related groaning type noises that could be misinterpreted as catathrenia include some types of snoring, and the moaning noises that may be made during an epileptic seizure. People with catathrenia usually have calm facial expressions and peaceful sleep despite the noise. The easiest way to distinguish snoring from catathrenia is that snoring occurs while inhaling, and groaning while exhaling. A careful examination of a partner’s breathing pattern in conjunction with the noises should be able to clarify which of the two it is.

Most people with catathrenia are not bothered by their own groaning, and will not rouse due to it, though it may be quite loud and potentially sleep disturbing to a bed partner. Most people with catathrenia will not even be aware of the disorder unless told by a bed partner, and likely will not believe the partner when told. Groaning appears to affect more males than females, and can start at any age. It appears in most cases that the groaning remains for many years. Subjects may wake up with sore throats the next morning, depending on the extent of the groaning the night before.

As the catathrenia has little to no effect on a person’s sleeping quality, and bears no connection at present to any other disorders that may be causing it, or that it may lead to, it may be unnecessary to have it looked into. If the disorder is causing distress to a bed partner, the easiest course of action may be for the partner to wear ear plugs while sleeping.

If it is decided to have a doctor look into it, they will need to know to the best of your knowledge when the groaning started, any medications you may be taking and any other sleeping disorders you may have. There is some thought that medication use may cause catathrenia in some patients, but there are no statistics to support this yet.
You may be asked to take an overnight sleep study to give the doctors a sense of the severity of the groaning, and to help detect any other sleeping disorders that may be present. As catathrenia is considered separate from other disorders, and unrelated to any other medical issues, this may be unnecessary.

There is limited data on effective treatment plans, but there is some evidence to suggest that positive airway pressure (PAP) may be beneficial in limiting the frequency and ferocity of catathrenia.

It is believed that catathrenia occurs most often during the rapid eye movement (REM) stage of sleep; however, there are studies that have found it to be present during all stages of sleep.  It is not the same as sleep apnea or regular snoring, as the person often wakes up feeling fully rested, even though their bed partner will probably not say the same.

Catathrenia is a condition that is more bothersome to a spouse or bed partner than it is to the individual; however, there are some cases where the person will awaken with expiration due to oxygen desaturation; therefore, many studies have suggested this condition may be a feature of sleep-disordered breathing.

What the Research Shows about catathrenia

With its inclusion as a parasomnia into the International Classification of Sleep Disorders Diagnostic and Coding Manual (ICSD-2) about a decade ago, catathrenia has made its way into the sleep medicine nomenclature, but with much debate about its causes, treatments, and background.

One study, done in 2008, which was published in the journal, SLEEP, was performed to try to determine if catathrenia was a symptom of sleep-disordered breathing or a condition all on its own.  Researchers also wanted to determine if previous literature was correct in reporting that CPAP (continuous positive airway pressure) was a viable treatment option for someone with catathrenia.

CPAP is the primary form of treatment for someone with sleep apnea or sleep-disordered breathing.

In this particular study, which was performed at the Stanford Sleep Disorders Clinic, seven women between the ages of 20 and 34 years with an average BMI of less than 25 were studied over a period of five years.  Each of the women (or their partners) had reported ongoing, long-term sleep groaning.

All participants in the study underwent clinical evaluation, sleep questionnaires, physical examination, an overnight sleep study, a log provided by their sleep partner for 10 days noting when and how long the groaning occurred, and craniofacial evaluation (looking for septal deviation, structure deformity, turbinate enlargement, etc., which can all affect breathing).

CPAP was administered to all seven women, but if they could not tolerate the CPAP machine, which is noisy and can be uncomfortable, then they were offered the option of undergoing a special soft tissue/upper airway surgery.

Groaning was present in all stages of sleep, which was relieved in all participants who used CPAP.

Five of the women elected to undergo surgery, only three of which followed up after the procedure and were given additional oral appliance treatment.  All three women experienced ultimate resolution of catathrenia more than three years later.

Causes and Background of Catathrenia

It is still unclear what causes the nighttime groaning or who is more likely to suffer the condition.  Some studies found that there was a similarity in cases concerning the size of their jaw (all patients have a small jaw).  Furthermore, about 14% of patients reported a positive family history of catathrenia.

In this study at Stanford, it was noted that 43% of participants had a past history of some sort of parasomnia (such as sleep talking) in childhood, 86% had orthodontic procedures, and 71% had tooth extractions in adolescence.

 Tips for Living with Catathrenia

Since catathrenia is not a particularly dangerous condition and is not associated with the development of more concerning health problems, there has been very little research in the way of determining origin and treatment options.  It is notable that the studies mentioned in this article are very small scale, with a group of people who were otherwise healthy.  Further research will be needed to determine best courses of treatment.

On the other hand, Dr. Roxanne Valentino of St. Thomas Center for Sleep recommends some ways to help bed partners deal with catathrenia.  These include:

  • Don’t panic: Catathrenia is harmless.
  • Listen: Catathrenia could potentially mask other problems, such as apnea.  Groaning happens on exhalation, there are very few nighttime awakenings, and the person will usually feel well rested upon awakening.  Listen for other abnormal sounds, like wheezing, gasping on inhalation, or excessive snoring.
  • White Noise: A fan or humidifier would be good options to block out some of the groaning noise.
  • Earplugs: These are helpful if the groaning is mild.
  • Seek Medical Attention: If all else fails, talk to a doctor or sleep specialist about obtaining a study or possibly undergoing CPAP treatment.


  1. Catathrenia. (2011, June). Retrieved July 05, 2016, from
  2. Guilleminault, C., Hagen, C. C., & Khaja, A. M. (2008). Catathrenia: Parasomnia or Uncommon Feature of Sleep Disordered Breathing? Retrieved July 05, 2016, from
  3. Romano, N. (2012, January 26). 5 Tips For Battling Catathrenia. Retrieved July 05, 2016, from
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