Although alcohol initially acts as a sedative, bedtime drinking is associated with sleep disturbances marked by slow wave sleep (SWS) electroencephalogram (EEG) activity delta waves. Normally developing adolescents aged 12-16 years have significantly reduced EEG delta waves, which is usually the age at which alcohol use begins. A study of the effects of alcohol on sleep in school college students found that drinking before sleep not only caused an increase in SWS-related delta waves, but also led to an increase in frontal alpha waves that interfered with markers of sleep. The findings were published online in February 2015 in the journal Alcoholism: Clinical & Experimental Research. The study was done by Christian L. Nicholas, MD, from the University of Melbourne, Australia, and a total of 24 participants (12 women, 12 men), healthy, 18-21 years old, social drinkers, who consumed less than seven standard drinks per week for the past 30 days were recruited in its trial. Each participant drank alcohol before bedtime, or placebo, followed by standard polysomnography monitoring with a full EEG recording. The results showed that alcohol increased delta waves during non-rapid eye movement (NREM) sleep, with a concomitant increase in frontal alpha. The study concluded that pre-bedtime alcohol consumption did not improve sleep quality and increased the duration of deep sleep.