A Medical History of Alcoholic Blackouts Should Put Multiple Personality in the Differential Diagnosis (the list of diagnoses to be considered)

Amnesia for the period of time that a person was intoxicated is usually assumed to be alcohol-induced, which may be true in many cases. But it is a correlation, not necessarily cause and effect, since many young alcohol bingers, and many chronic alcoholics, never do get blackouts.

Researchers tend to attribute the failure of many drinkers to get blackouts to the possibility that they don’t drink enough in a short enough period of time, or to genetic differences. They may be right, but they should also consider that something else may cause the memory gaps.

A person with multiple personality, who has an alternate personality who drinks, might very well have amnesia for the period of time that the alcoholic alter was out and about. This would be even more likely if the amnesia were for behavior that was out-of-character.

In some cases, the out-of-character, regrettable behavior—for which the person has amnesia—may have taken place when the person had not been drinking, or at least had not been drinking that much. Many people would rather claim they had an alcoholic blackout than admit they just do things they don’t remember, which sounds crazy.

In the articles I’ve read about alcoholic blackouts, they never say whether the participants in the research have ever had memory gaps, even small ones, when they had not been drinking. I recommend that they ask, since a person with multiple personality, who has an alter who drinks, will also have other alters who don’t drink, causing “dry blackouts.”

But isn’t multiple personality too rare to consider? Well, according to DSM-5, multiple personality disorder (dissociative identity disorder) occurs in 1.5% of the general population. And according to this blog, 90% of novelists, and perhaps 30% of the public, have what I call normal multiple personality, a high-functioning version.