Disturbed sleep in patients complaining of chronic pain.

Polygraphic recordings of the sleep of patients complaining of insomnia has led to recognition of specific patterns of disturbed sleep corresponding to different etiologies of insomnia. This study presents results of polygraphic recordings of the sleep of 26 patients with chronic pain for which no physical cause can be found. All 26 also complained of insomnia. Sleep parameters of this group were compared with those to two other groups also complaining of insomnia: 12 patients whose disturbed sleep was judged secondary to psychiatric disorder, and 16 patients with the subjective complaint of insomnia in whom no objective evidence of sleep disturbance could be demonstrated. The three groups differed significantly in terms of their sleep parameters. The pain patients slept less than the subjective insomnia patients. The sleep disturbance of the psychiatric patients was more severe than that of the chronic patients. Several chronic pain patients showed evidence of nocturnal myoclonus; several also showed alpha rhythm intrusions into their sleeping electroencephalograms. The study verifies that chronic pain patients do experience significant sleep disturbance and raises several questions concerning relationships among chronic pain, sleep disturbance, and psychiatric illness, particularly depression.