A case-control study of sexualised behaviour in sleep: A strong association with psychiatric comorbidity and relationship difficulties

Sexualised behaviour in sleep (SBS) is a relatively rare parasomnia consisting of instinctive behaviours of a sexual nature occurring during non-rapid-eye movement (NREM) sleep. Little information exists at present regarding the clinical features and onset of this condition as well as its link to psychiatric comorbidity, other sleep disorders and history of adverse early life experience. Aims were to typify the condition further and compare features of SBS patients to those with other NREM parasomnias.

Methods: Details of 335 consecutive patients presenting to a single tertiary sleep centre with non-rapid eye movement (NREM)-parasomnias over a 15-year period (2005–2020) were examined. Data were collated by reviewing case-notes for anthropometric data, past medical history, clinical findings, and video polysomnography. SBS patients were compared to a cohort of 270 non-SBS, NREM-sleep disorder patients (case-control) to ascertain whether they had any distinguishing features from other parasomnias classified in this group.

Results: Sixty-five patients with SBS were identified: 58 males, 7 females (comprising 19.4% of the cohort overall). Mean age at presentation was 33(±9.5) years. Onset of behaviours was commoner in adulthood in the SBS cohort, whereas non-SBS, NREM-parasomnia onset (n = 270) was commoner in childhood: 61.1% and 52.9% respectively (p = 0.007). An association was identified between the presence of psychiatric diagnoses and onset of SBS (p = 0.028). Significant triggers for SBS behaviours included alcohol consumption (p < 0.001), intimate relationship difficulties (p = 0.009) and sleep deprivation (p = 0.028). Patients with SBS were significantly more likely to report sleepwalking as an additional NREM behaviour (p < 0.001). Males were more likely to present at clinic together with their bedpartner and females presented alone. A history of SBS appeared to be more common in those working in the armed forces or the police compared to those presenting with non-SBS, NREM-parasomnias (p = 0.004).

Conclusions: SBS is more common in clinical practice than previously described and presents with some distinguishing features within the NREM disorder category. This study is the first to identify that onset in childhood or lack of amnesia does not preclude the condition and that patterns of presentation differ between men and women. Sleepwalkers particularly should be asked about SBS. Comorbid psychiatric conditions, profession and intimate partner difficulties are strong determinants of the presentation.