Insomnia: often a therapeutic challenge.

Insomnia, a more or less chronic sleep disturbance, is a very common symptom in psychiatric patients but also relatively freguent in the general population to a lesser degree. Two broad types of insomnia may often be distinguished: (1) difficulty falling asleep and frequent wakening, characteristic of anxiety states or obsessive worrying; and (2) early morning wakening, sometimes in a panic, suggestive of endogenous depression. The first group of patients respond well to minor tranquilizers and psychotherapy, whereas the second do well with tricyclic anti-depressants. Many studies in sleep laboratories have declineated the stages and cycles of sleep physiology and pathology, especially the importance of REM or dreaming sleep. The clinician should be cautious in the use of hypnotics like barbiturates which suppress REM sleep and produce a rebound increase on withdrawal, as well as problems of dependence of habituation. Flurazepam and chloral hydrate are considerably safer in this respect. Understanding sleep neurophysiology and biochemistry permits appropriate individual clinical management for both psychiatric patients and medical patients with conditions like peptic ulcer and nocturnal angina pectoris.