Excessive alcohol consumption can lead to blackouts – periods of temporary memory loss or amnesia. Blackouts are common among alcohol abusers and can be a warning sign to drinkers and their friends that alcohol-related problems exist. Blackouts are also considered an early high-risk indicator of alcoholism. For problem and healthy drinkers alike, blackouts are often troubling or traumatic when serious and typically unforgettable occurrences are impossible to remember.

Alcohol has far reaching effects on many areas of the brain. When you consume alcohol, the body immediately begins to break it down. In the process, breakdown products called ethyl esters speed the movement of positively charged potassium ions from brain cells through the outer membranes, creating a negative charge within the cell. This impairs calcium channels, which brain cells rely upon to communicate with other cells throughout the body. The brain also receives less oxygen when alcohol is present. Alcohol also has a detrimental effect upon the central nervous system. The cumulative effect of these changes is that the activity of the hippocampus is disrupted. Moderate doses of alcohol disrupt the acquisition and performance of spatial reference memory tasks, and reduce the overall level of glutamate released at synapses within the hippocampus.