Altered sleep physiology in chronic alcoholics: reversal with abstinence.

Somnograms obtained from recently abstinent chronic alcoholics reveal gross disruption succinctly described as "fractured" sleep. Sleep onset is delayed and the rhythmic properties of the sleep pattern are markedly disturbed with numerous brief arousals and changes of sleep stage. Excessive stage 1 and stage rapid eye movement sleep are present while the high voltage slow wave sleep is markedly reduced or absent. With continued sobriety (9 mo or more) the sleep stage percentages tend to return to normal levels, but the disruption of the sleep pattern persists after as much as 21 mo of abstinence.