Fear of Sleep

Which factors the inventory found

Researchers gave the short form of the Fear of Sleep Inventory to two samples of undergraduate women who reported a history of potentially traumatic events, 339 in the first and 318 in the second, alongside other psychological and sleep measures. They ran an exploratory factor analysis on the first sample and a confirmatory analysis on the second.

In the women whose history included sexual trauma, four latent factors fitted the data:

• vigilance
• fear of the dark
• fear of nightmares
• vulnerability

The structure held in the second sample and showed appropriate convergent and discriminant validity against the other measures.

In the women reporting other kinds of potentially traumatic event, it did not fit.

That result says something unusual about a fear. Its internal structure depends on what happened to the person, which means fear of sleep is not one thing measured in different amounts. It is at least two different arrangements of worry that produce similar answers on a questionnaire.

Why the nightmare factor is separable

The authors' specific conclusion is that for women with a history of sexual trauma, fear of nightmares appears distinct from the other facets of the construct.

That matters for treatment. A person kept awake by vigilance is guarding against something in the room; a person kept awake by fear of nightmares is guarding against something that only exists once they are asleep. The first can be addressed by securing the room and the second cannot, and a single label covering both will send some patients to the wrong intervention.

What the sleep literature calls it

Somniphobia is the Latin form, hypnophobia the Greek, and clinophobia takes the bed rather than the sleep. All three circulate for the same thing.

None of them appears in the International Classification of Sleep Disorders, which sorts sleep problems into insomnia disorders, sleep-related breathing disorders, central disorders of hypersomnolence, circadian rhythm disorders, parasomnias and sleep-related movement disorders. A person who cannot sleep because they are afraid to would be recorded as having insomnia, which is the commonest sleep disorder there is, and the reason would not appear in the code.

That is the practical consequence of the term's absence. The behaviour is counted and the motive is not.

Where the word circulates most

The word's widest circulation is a record. In Somniphobia, recorded between 2010 and 2011, is the ninth studio album by the Japanese extreme metal band Sigh, released on 13 March 2012 on Candlelight Records, and its fourth track carries the word as its title.

That is the third entry in this catalogue whose term is best known as a sleeve. Melophobia and Philosophobia are the others, and the pattern is consistent: a phobia name with no clinical weight makes a good title precisely because it sounds like a diagnosis and commits to nothing.