Sleep is promptly reversible, an important characteristic differentiating it from most other states of altered consciousness. A variant of Somnambulism, (a distinct sleep disorder in which motor acts are performed) known as sexsomnia, or “sleepsex” was first described in 1897 related to a case of somnambulism and exhibitionism (to a policeman).


Sexsomnia is often a longstanding disorder that carries major adverse physical, psychosocial, and legal consequences. Cases of sleep-related sexual abuse of children typically have even more drastic long-lasting consequences.

A crime committed during sleep is regarded in law as an, ‘automatism’, the legal definition as “the state of a person who, though capable of action, is not conscious of what he is doing….”. Proof of mens rea, (guilty mind) has to be proven before conviction.

cartoon of man walking in his sleep
Sleep walking

Penile tumescence cycles in sleep occur in all normal healthy males from birth into old age regardless of the dream content and may be related to sexomnia, although exhibitionism may be a side effect of sleep walking.

The Rape Defence?

Any conviction of rape will be likely if the defendant admits that the victim was unquestionably asleep and did not wake up during intercourse. Cases of “murdering while asleep” have been ruled guilty when the defendant shows recollection or insight.

Any history of sexsomnia must include a psychiatric assessment, detailed description of the event and degree of amnesia, current, past medical and family history.

The presence of potential precipitating factors such as stress; sleep deprivation, sleep fragmentation, alcohol or drug consumption, excessive tiredness, and physical over-activity in the evening should be investigated, along with the subject’s disorientation and attitude upon ‘awakening’.

Business woman yawning - sleep deprivation

With an increasing proportion of sleep deprivation in in adults as well as teenagers, its consequences must be considered.

In the older population, sleep fragmentation and sleep respiratory disorders (e.g. sleep apnea) are very prevalent and have been described to precipitate sexsomnia in subjects with previous history of somnambulism.

Dr. Colin Shapiro

In summary, this sleep disorder should receive more attention. This condition appears to be under-recognized and it is suggested that questions about sleep and sex be included in the clinical evaluation of suspected parasomnias.

It was the famous sleep researcher, Dr. Colin Shapiro, who, early in his career, while working as a researcher at a sleep laboratory in South Africa (1984), first stumbled across a case that would lead him to coin the term “sexsomnia.”

Sexsomnia used as a legal defense.

“The engine is running, but there’s no driver behind the wheel,” was how one defence lawyer described it.

… but he wasn’t talking about an out-of-control car, or a drunk driver.

Picture of a Sign - "only yes is yes"

The lawyer was mounting a defence in a rape trial, and telling the court that his client may have had sex with the woman he was accused of sexually assaulting, but he had no control over it, and no memory of it, as he was asleep.

Sexsomnia may be a term that incites a schoolboy jokes but for sufferers, and those close to them, it is a serious condition that can threaten relationships, and even result in prison.

Book with glasses on it - link to article
Sexsomnia as a Defense in Repeated Sex Crimes

Sleepwalking affects about one in 25 children, but 66 per cent of them grow out of it. Sexsomnia, most often experienced by adult males, is much less common.

Sexsomnia risk factors

Underlying medical conditions may trigger sexsomnia, too. These conditions often interfere with sleep.

Underlying factors that may trigger Sexomnia include:

Simultaneous sleep disorders, including sleep talking or sleepwalking

Restless leg syndrome

Obstructive sleep apnea

Sleep-related epilepsy

Gastroesophageal reflux disease (GERD)

Head injuries


Incidence of sexsomnia

It’s not clear how common sexsomnia is, but it’s considered rare. One study found that 8 percent of people at a Canadian sleep disorder clinic showed symptoms of sexsomnia. Men were almost three times more likely than women to have the disorder. Women with sexsomnia were more likely to masturbate.

Book with glasses on it - link to article
One study in Toronto, canada found that 8% of people at a Canadian sleep disorder clinic showed symptoms of sexsomnia.

Keep in mind the study results only included people at a specific sleep disorder clinic. The condition is likely much less common in the general population.

People experiencing the disorder may not report their symptoms because they may feel embarrassed or ashamed or be unaware of their condition.

That could mean more cases occur than are known. Of the 832 participants in a Canadian study, only four expressed concerns about sexsomnia during consultations with sleep specialists.

Book with glasses on it - link to article
The behaviour may be more common than previously thought.

Seeking help for Sexsomnia

Doing things you can’t recall doing while you were asleep can be alarming. Some sexsomnia behaviours may be harmless, such as masturbating. For others, they can also be quite serious – and sexsomnia has been used as a defenseTrusted Source in rape cases.

Book with glasses on it - link to article
Sexsomnia: Sleep Sex Research and Its Legal Implications

Partners of people with sexsomnia may also be concerned the behaviour is a sign of displeasure in the relationship. This can lead to a growing rift between you and your loved one.

These are all valid reasons to seek help for your sleep disorder. If a partner or loved one reports unusual sleep behaviours to you over the course of a few weeks or months, make an appointment with a sleep specialist. If you don’t know one, ask for a recommendation from your family doctor.

The diagnosis of Sexsomnia

Before seeing your doctor, ask anyone who has observed your sleep sex behaviours to write down what they’ve seen. You should also keep a journal of your sleep patterns.

A record of these sleep sex episodes may be enough for your doctor to diagnose the condition. If it isn’t, they may request that you undergo a sleep study.

Sleep studies are typically conducted at specialized medical facilities. The test, also called polysomnography, records the following during sleep records various body functions, such as brain waves, blood pressure, breathing, etc.

One night in the sleep centre may be enough. Your doctor may also request you stay multiple nights so they can get a broader understanding of your sleep patterns. If the behaviours occur while you’re in the sleep centre, this can confirm your doctor’s diagnosis.

If a sexsomnia episode doesn’t occur while you’re in the study center, your doctor may request additional studies later. They may also try other tests to rule out possible causes.

The treatment of Sexsomnia

Treatment for sexsomnia is often very successful and include – dealing with underlying sleep disorders

If sexsomnia is possibly the result of another sleep disorder – like sleep apnea or restless leg syndrome, treating the underlying disorder may also stop the unintended sexual behaviours. Sleep apnea, for example, is most often treated with continuous positive airway pressure (CPAP) or a dental appliance (Oral Appliance Therapy – OAT).

While the cause of sexsomnia is still unknown, and the episodes are considered random, researchers think that people are triggered into them when there’s a disruption in the brain as it moves between deep sleep cycles.

It’s also thought sleep deprivation, alcohol consumption, or sleeping pills like Ambien increase someone’s likelihood of experiencing sexsomnia.

While at Harvard’s Children’s Hospital in Boston I was fortunate enough to spend time with Dr. Sanjeev Kothare and can recommend his book as a comprehensive guide to a fascinating aspect of sleep – not for the fainthearted or short attention span!

Book - Parasomnias

Parasomnias also include: 


Confusional Arousals

Sleep Terrors

Sleep Eating Disorder

REM Sleep Behavior Disorder

Nightmare Disorder

Sleep Paralysis

Bedwetting (enuresis)

Sleep Hallucinations

Exploding Head Syndrome

Sleep Talking

Treatments can also include medication to improve sleep, counselling, or avoiding triggers like alcohol and sleeping medications.

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