Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find the Narcolepsy and Cataplexy article more useful, or one of our other health articles.
Treatment of almost all medical conditions has been affected by the COVID-19 pandemic. NICE has issued rapid update guidelines in relation to many of these. This guidance is changing frequently. Please visit https://www.nice.org.uk/covid-19 to see if there is temporary guidance issued by NICE in relation to the management of this condition, which may vary from the information given below.
What are hypnagogic hallucinations?
Hypnagogic or hypnopompic hallucinations are visual, tactile, auditory, or other sensory events, usually brief but occasionally prolonged, that occur at the transition from wakefulness to sleep (hypnagogic) or from sleep to wakefulness (hypnopompic). The phenomenon is thought to have been first described by the Dutch physician Isbrand Van Diemerbroeck in 1664. The person may hear sounds that are not there and see visual hallucinations. These visual and auditory images are very vivid and may be bizarre or disturbing.
- Excessive daytime sleepiness
- Hypnagogic hallucinations
- Sleep paralysis
This tetrad is rarely seen in children.
See the separate Narcolepsy and Cataplexy article.
How common are hypnagogic hallucinations? (Epidemiology)
- Hypnagogic hallucinations can occur without narcolepsy. People may be reluctant to admit to them for fear of being thought mentally ill. However, they are thought to occur in most people at least once in their lives.
- A UK study had 37% of the sample reported experiencing hypnagogic hallucinations, and 12.5% reported hypnopompic hallucinations. Both types of hallucinations were significantly more common among subjects with symptoms of insomnia, excessive daytime sleepiness or mental disorders.
- A recent study had a prevalence for hallucinations in the auditory domain (the least common type) at 6.8%, whereas 12.3% reported multimodal hallucinations, and 32.2% indicated out-of-body experiences at the onset/offset of sleep.
- Group comparisons of hallucinations in the auditory modality showed that individuals who experienced only auditory hallucinations scored significantly (p <0.05) lower than those who also experienced daytime auditory hallucinations on a range of variables including mental health, anxiety, childhood happiness, and well-being.
Risk factors for hypnagogic hallucinations
- There is a tendency for hypnagogic and hypnopompic hallucinations associated with narcolepsy to be associated with certain HLA phenotypes.
- Tricyclic antidepressants have been reported to be associated with hypnagogic and hypnopompic hallucinations.
Hypnagogic hallucinations symptoms
Narcolepsy is often under-diagnosed and delays of 5-10 years are common before making a firm diagnosis. Close to 50% of patients develop symptoms in their teenage years:
- Hypnagogic hallucinations can occur at the onset of sleep, either by day or at night. They are usually quite vivid and visual.
- Visual hallucinations usually consist of simple forms such as coloured circles or parts of objects that may be constant or changing in size. A formed image of an animal or a person may appear and it is often in colour.
- Auditory hallucinations are common but other senses are seldom involved. Auditory hallucinations can range from a few sounds to an elaborate melody. Threats or criticism are also reported.
- Another type of hallucination that is sometimes reported at the onset of sleep involves elementary cenesthopathic feelings (such as experiencing picking, rubbing, or light touching), changes in location of body parts (such as an arm or a leg), or feelings of levitation or extracorporeal experiences (like moving the body in space or floating above the bed) that may be quite elaborate.
- There may be a history of narcolepsy with the ability to fall asleep if at all tired or bored, often with social embarrassment. It may lead to the inability to hold down a job.
There are usually no abnormal physical signs.
- It is important to decide if this is narcolepsy, as it is a treatable condition.
- Schizophrenia can cause hallucinations, including derogatory auditory remarks.
- Musical release hallucinations are complex auditory phenomena, affecting mostly the deaf elderly population, in which individuals hear vocal or instrumental music. Progressive hearing loss from otosclerosis disrupts the usual external sensory stimuli necessary to inhibit the emergence of memory traces within the brain, thereby 'releasing' previously recorded perceptions.
- There may be drug misuse.
- Sleep terrors in children.
- Focal seizures.
- Absence seizures.
- Blood tests and imaging are likely to be normal.
- Referral to a special sleep laboratory may be required to diagnose narcolepsy.
Hypnagogic hallucinations treatment and management
- Hypnagogic hallucinations can be treated with REM-suppressing antidepressants, such as venlafaxine (Effexor®) or other selective serotonin reuptake inhibitors[9, 2].
- Fluoxetine has also been recommended for this indication.
- Musical hallucinations may be helped by olanzapine, quetiapine, fluvoxamine, clomipramine, carbamazepine, valproate and donepezil.
- Sodium oxybate is as effective as modafinil and pitolisant as treatment for cataplexy but it should not be combined with other CNS depressants or alcohol. Sodium oxybate is also known as GHB, a known street drug of abuse.
- Pitolisant, an H3 receptor antagonist, and solriamfetol, a dopamine and noradrenaline reuptake inhibitor, are the most recently approved treatments for EDS associated with narcolepsy in the European Union (pitolisant) and the USA (pitolisant and solriamfetol).
For the treatment of narcolepsy, see the separate Narcolepsy and Cataplexy article.
If the patient has narcolepsy the prognosis is as for that disease. If not, reassurance is all that is required. If it disturbs the patient, medication may be used intermittently.
Further reading and references
Waters F, Blom JD, Dang-Vu TT, et al; What Is the Link Between Hallucinations, Dreams, and Hypnagogic-Hypnopompic Experiences? Schizophr Bull. 2016 Sep42(5):1098-109. doi: 10.1093/schbul/sbw076. Epub 2016 Jun 29.
Akintomide GS, Rickards H; Narcolepsy: a review. Neuropsychiatr Dis Treat. 20117:507-18. doi: 10.2147/NDT.S23624. Epub 2011 Sep 8.
Kompanje EJ; 'The devil lay upon her and held her down'. Hypnagogic hallucinations and sleep paralysis described by the Dutch physician Isbrand van Diemerbroeck (1609-1674) in 1664. J Sleep Res. 2008 Dec17(4):464-7. Epub 2008 Aug 5.
Golden EC, Lipford MC; Narcolepsy: Diagnosis and management. Cleve Clin J Med. 2018 Dec85(12):959-969. doi: 10.3949/ccjm.85a.17086.
Ballas P; First-Known Hypnopompic Hallucination: Occurring In-Hospital: Case Report, 2006
Ohayon MM, Priest RG, Caulet M, et al; Hypnagogic and hypnopompic hallucinations: pathological phenomena? Br J Psychiatry. 1996 Oct169(4):459-67.
Bless JJ, Hugdahl K, Krakvik B, et al; In the twilight zone: An epidemiological study of sleep-related hallucinations. Compr Psychiatry. 2021 Jul108:152247. doi: 10.1016/j.comppsych.2021.152247. Epub 2021 May 18.
Watson NF, Ton TG, Koepsell TD, et al; Does narcolepsy symptom severity vary according to HLA-DQB1*0602 allele status? Sleep. 2010 Jan33(1):29-35.
Cancelli I, Marcon G, Balestrieri M; Factors associated with complex visual hallucinations during antidepressant treatment. Hum Psychopharmacol. 2004 Dec19(8):577-84.
Slowik JM, Collen JF, Yow AG; Narcolepsy
Management of Common Sleep Disorders; American Family Physician
Moturi S, Ivanenko A; Complex diagnostic and treatment issues in psychotic symptoms associated with narcolepsy. Psychiatry (Edgmont). 2009 Jun6(6):38-44.
Vitorovic D, Biller J; Musical hallucinations and forgotten tunes - case report and brief literature review. Front Neurol. 2013 Aug 84:109. doi: 10.3389/fneur.2013.00109. eCollection 2013.
Lehert P, Falissard B; Multiple treatment comparison in narcolepsy: a network meta-analysis. Sleep. 2018 Dec 141(12). pii: 5102365. doi: 10.1093/sleep/zsy185.
Thorpy MJ; Recently Approved and Upcoming Treatments for Narcolepsy. CNS Drugs. 2020 Jan34(1):9-27. doi: 10.1007/s40263-019-00689-1.