Sydney, Oct 1 : Long-term alcoholism affects sleep even after long periods of abstinence, impacting men and women similarly, says a new study.

The study indicates that in long-term alcoholics who had not had a drink for up to 719 days, the percentage of slow wave sleep or deep sleep was significantly lower.

Slow wave sleep and more light stage 1 sleep is reflective of poorer sleep quality, which could act as an exacerbating factor in alcoholics' cognitive decline.

Although women had better sleep efficiency and fewer wake periods than men, no significant interactions between sex and alcoholism diagnosis were found for any measures.

This suggests that women show the same general pattern of alcoholism-related sleep changes as men.

Principal investigator Ian Colrain, psychologist at the University of Melbourne, was also surprised to find that a significant increase in the percentage of rapid eye movement (REM) sleep, usually associated with dreams, persisted in alcoholics who had abstained for an extended period.

The study involved 42 alcoholics who were recruited from an inpatient treatment programme and 42 controls.

Estimated lifetime alcohol consumption was significantly higher in male alcoholics (1,607.2 kg) than female alcoholics (843.7 kg).

Many aspects of psychological functioning are affected by damage to the frontal cortex of the brain, including those that relate to judgement and risk taking, said Colrain.

The study appeared in the Thursday edition of Sleep. (ians)