The complex nature of insomnia and its relationship with organic and mental disorders render diagnosis problematic for epidemiologists and physicians.
A representative UK sample (non-institutionalised, > 14 years old) was interviewed by telephone (n=4972; 79.6% participation rate) with the Sleep-EVAL system. Subjects fell into three groups according to presence of insomnia symptom (s) and/or sleep dissatisfaction.
Insomnia symptoms occurred in 36.2% of subjects. Most of these (75.9%), however, reported no sleep dissatisfaction. In comparison, those also with sleep dissatisfaction had higher prevalence of sleep and mental disorders and longer duration of insomnia symptoms, and were more likely to take sleep-promoting medication, dread bedtime, and complain of light sleep, poor night-time sleep and daytime sleepiness.
Insomnia sufferers differ as to whether they are satisfied or dissatisfied with sleep. Although insomnia symptoms are common in the general population, sleep disturbances among sleep-dissatisfied individuals are more severe. Sleep dissatisfaction seems a better indicator of sleep pathology than insomnia symptoms.