Explanations of Insomnia

Primary insomnia can be learnt through association after experiencing stress-related insomnia. When insomnia occurs that is a result of stress and anxiety, an association forms between the bed and sleeplessness, so insomnia persists even when stress disappears. Sleep-related anxiety and the expectation of insomnia leads to learned insomnia, in a self-fulfilling prophecy.

This explanation of insomnia has found valuable real-world application in the use of CBT (cognitive behavioural therapy) to treat primary insomnia - breaking the association between the bed and sleeplessness to reduce anxiety over being unable to sleep. The success of this therapy supports the learnt explanation of insomnia - if the disorder can be unlearned through therapy, this suggests that it was a learnt behaviour in the first place.

Research by Storms and Nisbett supports the hypothesis of learned insomnia. In a clinical trial of insomniacs, participants went to sleep faster on placebo pills they believed to be stimulants, attributing their state of wakefulness to the pill rather than insomnia, so they relaxed enough to go to sleep. The group given pills they believed to be anxiolytics took even longer to get to sleep than normal, assuming that their insomnia was unusually severe that night due to their unaltered level of wakefulness. This supports the suggestion of self-generated anxiety over insomnia being a causal factor in the perpetuation of insomnia.


Gender differences in the diagnosis of primary and secondary insomnia suggests that this theory may be beta gender biased in its explanation of insomnia. The incidence rate of insomnia is higher in females, who also tend to have higher levels of anxiety and neuroticism - this supports the concept of stress as a factor which can lead to learned insomnia, but suggests that it is inaccurate to attribute the same cause to both sexes, as they experience the condition differently, with females more prone to stress-induced insomnia. It would be gender biased to assume that insomnia has the same causes in both males and females.

The genetic explanation of insomnia explains the condition as a result of an inherited gene defect in the genes responsible for the healthy function of the brain stem, leading to irregularities with the sleep/wake cycle. This is based on the observation that insomnia starts early on in life in most sufferers, suggesting that an innate biological cause rather than a learned behaviour is responsible.

Research by Watson et al supports the role of genes in the development of insomnia, studying 1800 pairs of twins. The concordance rate in genetically identical, monozygotic twins was 47%, while the concordance rate in non-identical, dizygotic twins was only 15%. This increased concordance rate in monozygotic twins supports the concept of a genetic basis for insomnia, but shows that genetics cannot completely explain the condition - monozygotic twins are completely genetically identical, so if the condition was entirely genetic in origin, they would show a 100% concordance rate. 

Although Watson et al's observed concordance rates would support the role of nature in the development of insomnia, twin studies alone are not enough to separate the influences of nature and nurture when determining a condition's origin. Monozygotic twins tend to be treated more similarly and share more similar environments than dizygotic twins, meaning that the higher concordance rate may be due to monozygotic twins sharing more environmental factors that could lead to the development of insomnia, such as stress, sleep deprivation and obesity. The concordance rates of obesity were markedly high between both types of twin - it is possible that the increased concordance rate of insomnia in monozygotic twins was a result of an increased concordance rate of obesity, a factor known to contribute to insomnia. 

Dauviliers and Tafti found further supporting evidence for the genetic explanation of insomnia, identifying several gene mutations implicated in the disorder. They also pointed to the genetic illness fatal familial insomnia as supporting evidence - an incredibly rare and heritable prion disease presenting in middle age which leads to a gradual death from sleep deprivation. The heritable nature of this disease suggests that some forms of insomnia have a definite genetic basis.