Dear Dr. Jeff: Many people I know on campus have "blacked out" from drinking during a weekend now and then. Is it anything to worry about? M. M.
Dear M.M.: I'm not sure if you're referring to memory loss from drinking or to actually losing consciousness from drinking. Let's look at both.
"Blackouts" are chemically induced periods of amnesia, which can last for seconds, minutes, hours and even days. They are caused by blood alcohol levels high enough to interfere with normal brain function (in this case, the formation of short-term memory).
They can occur "en bloc" (blackouts with a beginning and an end, containing "lost time," which can themselves be recalled as events) or as "fragments" (memory lapses about which the drinker remains unaware until someone reports them back).
Although they can occur in normal, healthy drinkers who have over-indulged, blackouts are always and unquestionably a warning sign of problematic drinking.
The appropriate response to your first blackout should be to be frightened, and to re-evaluate your drinking patterns and habits.
Recurring blackouts are considered early, high-risk indicators of alcoholism. Some drinkers experience them early in their drinking, others later. Blackouts are definitely associated with binge drinking, extended drinking over long periods of time, drinking while fatigued, and drinking on an empty stomach.
Researchers have proposed a genetic basis for increased risk of blackouts. Some people seem simply to metabolize alcohol less efficiently. Others may have a greater neurologic sensitivity to the toxic effects of alcohol. Both groups are thought to share some of the genetics and neurobiology that underlie alcoholism.
Whatever their longer-term risks, blackouts are a clear sign of immediate danger. If inhibitions are lowered and judgment impaired by more moderate drinking, imagine how much greater your risks are when drinking to blackout levels.
Though conscious, you are operating at a level of intoxication where your brain is literally incapable of processing information. You will certainly do things you won't remember. You may well do things you wouldn't want to remember.
Heavy drinking can, of course, also lead to loss of consciousness, especially for people with lower tolerance to alcohol. If you raise your blood alcohol high enough or quickly enough, you'll most likely begin to vomit (that's your body's way of trying to get rid of excess alcohol in a hurry.) You may end up passing out, a sign that you've been alcohol-poisoned.
Passing out is very simply an indication that your brain can no longer tolerate that level of toxicity. Passing out from drinking is always a sign of dangerous drinking.
So, M.M., blacking out "now and then" is very definitely something to worry about. Whether you're referring to alcohol-induced amnesia or to passing out, you're describing signs of dangerous drinking.
Obviously, college students are going to drink. I'm just hoping I can help you understand how to drink safely and responsibly. Know your limits. Pace yourself appropriately. Don't drink alone, and whatever you do, don't drink and drive.
Cheers!
Jeff Benson, MD
Dudley Coe Health Center