Facing the Dread of a Demon- Incubus Syndrome case report

Incubus syndrome is usually noticed in patients with schizophrenia or along with other delusions in a delusional disorder. But patients having incubus phenomenon alone without any other psychotic symptoms have never been reported. Varadharajan et al have reported one such unusual case in the current edition of Indian Journal of Psychiatry who was successfully managed with antipsychotics.

The case provides a learning opportunity for psychiatrists as such presentations can prove a surprising challenge in their clinical practice. "Incubus" as per mythological beliefs refers to a male demon who rapes women during sleep.

A 45-year-old female who presented with a history of strange sexual experiences occurring during sleep for the past 4 years. Having separated from her husband, she had been living alone for the past 14 years. She initially reported someone having sexual intercourse with her every night during sleep. She woke up in fear (about 1 h after falling asleep) and to her surprise, no one was around. She clearly described feeling the pressure of someone lying on her and the to and fro motion of phallus in her vagina.

Even on trying sleeping during the daytime, these symptoms endured, nearly every day. She visited faith healers and even changed her religion to stop them but no relief obtained. She remained preoccupied and distressed with these beliefs throughout the day and to relief the same, she self-medicated herself with sedative-hypnotic agents but to no avail.

She was convinced that it was a deceased's spirit who was indulging in sexual acts with her. She described the deceased as a young guy, who during his brief stay in her home, had made sexual advances toward her multiple times, and hence had to be sent back to his parents. A few months later, she heard that he committed suicide. She felt guilty and responsible for his death. Her symptoms started a week after his death.

There was no history suggestive of any other comorbid psychiatric diagnosis (posttraumatic stress disorder, schizophrenia, depression, narcolepsy, cognitive deficits, and other substance abuse) or organicity. All the basic investigations and computed tomography of brain were normal. Parasomnias were ruled out by history, and hence polysomnography was not done. A diagnosis of psychosis not otherwise specified (NOS) was made and initiated her on tablet olanzapine and titrated it to 10 mg/day. She reported complete improvement of symptoms in a month. She is on regular follow-up for the past 3 months and continues to be asymptomatic.

The patient suffers from a variant of erotomania like phantom lover syndrome but occurring during sleep. Hence, a diagnosis of psychosis NOS (atypical incubus syndrome) was made. Complete resolution of symptoms with olanzapine points to an underlying psychotic illness. Careful history must be sought to rule out the presence of other psychotic symptoms and parasomnias.

Source: Indian Journal of Psychiatry : Varadharajan N, Bascarane S, Menon V. Atypical incubus syndrome: A case report. Indian J Psychiatry 2021;63:203-4.