Sleep Related Abnormal Sexual Behaviors: Uncommon yet Grave!

Abstract

Sexual activities during sleep have been reported by some people, often along with the amnesia for the same. Such activities, when involuntary, may arise because of disorders of arousal or may be attributed to sleep related seizures. However, differentiation between the two etiological factors and, also from voluntary acts committed during sleep-period is important not only for the management of disorders but for medicolegal purpose! Subjective information as well gathered by the patients, bed-partners or victims as objective measures, namely polysomnography, long-term video EEG, and neuroimaging techniques may be helpful in achieving the same.

Sleep related abnormal sexual behaviors (SRASB), also known as sexsomnia, have been classified as disorders of arousal (DOA) by International Classification of Sleep Disorders, 3rd edition. ¹ These disorders include a number of sexual activities that are performed during period of sleep and manifested as masturbation, intercourse with the bed partner, vocalization having sexual content loud enough to be heard by the bed-partner, and at times sexual molestation and assaults. ¹ Typically subjects have amnesia for the event after waking up. ¹ Though most of the events are limited in the bed and arise from the confusional-arousals, at times, sexual activity may be seen as a manifestation of or associated with somnambulism. ¹

SRASB appears to be a rare manifestation of sleep-related seizures and a recent report suggests that 0.12% cases referred for sleep-related seizures have semiology confirming with sexsomnia. ² Seizure activity in these cases usually arise from frontal or temporal foci and is related to activation of central-pattern generators. ² SRASB as a manifestation of sleep-related seizures was reported among females only, while male patients were diagnosed with disorders of arousal. ² Interestingly, in this case series, sleep-related seizures and disorders of arousal were not found to be comorbid, suggesting that co-existence of both disorders is unlikely in cases of SRASB. ²

Shenck et al ³ were the first to review published cases of SRASB. They reported that most common presentation was fondling other person and intercourse (nearly 45% each) followed by masturbation. ³

It is of paramount importance to differentiate whether SRASB is caused by an epileptic phenomenon or a disorder of arousal. Voges et al ² suggested that certain clinical and historical features favor epileptic origin, eg, sexual activity during wakefulness associated with amnesia, stereotyped sexual activity across episodes, other symptoms suggestive of epilepsy, lack of target for the sexual activity, arousal of the patient is not possible to interrupt the activity, and incomplete sexual intercourse. On the contrary, features favoring disorders of arousal include lack of stereotypy, absence of such episodes during wakefulness, well directed sexual behavior, possibility of terminating the episode by waking the patient, and completed sexual act if patient is uninterrupted. ² Besides these factors, recall is always absent in disorders of arousal; however, nearly 70% patients with sleep-related seizures are able to recall the event. ³ Patients with SRASB arising out of disorders of arousal also have historical evidence of confusional arousals, sleep-related eating disorder, sleep-walking, REM sleep behavior disorder, obstructive sleep apnea, and sleep-related bruxism.^1,3,4

Semiology of the behavior can also be used to differentiate between the two. Complex sexual behaviors like fondling other person or sexual intercourse have not been reported among subjects with sleep-related epilepsy. ³ Contrarily, sexual behavior in sleep-related epilepsy is dominated by ictal orgasm and experiential sexual arousal. ³ Lastly, masturbation and sexual vocalizations are reported in both conditions. ³

SRASB representing disorders of arousal, is not only a source of emotional distress to the patient, but at times result in physical injuries to the partner and are source of legal complications. ³ On the contrary, SRASB due to epilepsy are associated with injury to self rather than partner and hasn’t been reported to have legal consequences. ³ Lower legal consequence are related to the facts that SRASB due to epilepsy never involve minors as victims and, as already stated earlier, usually involve non-complex sexual activity.^2,3 It is interesting to note that law recognized the involuntary nature of sexual act due to the underlying disorder and trial in the court of law favored the defendant in most of the cases.^3,5

Besides historical evidence, objective investigations like video synchronized polysomnography and long-term video EEG can reliably be used to differentiate between the two.^2,6 Diagnosis of disorders of arousal is favored by lesser number of events per night (3 for DOA vs 6 for epilepsy), origin of episode during N3 and preponderance of events during first half of the night. ⁶ SRASB due to disorders of arousal often show other conditions that can interrupt continuity of sleep such as obstructive sleep apnea or REM sleep with atonia. ^1,3 However, as is true for other disorders of arousal, SRASB due to disorders of arousal is uncommon to be observed during whole night polysomnography; still it is strongly recommended as it can uncover other sleep disorders inducing interruption of sleep. ³

Fortunately, treatment of primary condition such as obstructive sleep apnea using positive airway pressure therapy and clonazepam can relieve SRASB representing disorders of arousal. ³

In conclusion, it is important to suspect SRASB in appropriate clinical scenario and use electrophysiology to differentiate the SRASB related to disorders of arousal from that related to epilepsy so as to manage them appropriately.