Ego alien, Egodystonic, Self-Contradiction: Thoughts, remarks, and behaviors that do not feel like your own, because they are due to alternate personalities.

Most things that most people think, say, and do are egosyntonic: they feel natural, like something you would expect yourself to think, say, or do. For example, if you have always loved chocolate ice cream, but have always detested vanilla ice cream, then purchasing and eating chocolate ice cream would be egosyntonic, but purchasing and eating vanilla ice cream would be egodystonic or ego alien. And if you found that you had purchased and eaten vanilla ice cream, you would think, “I don’t know what came over me. That’s not like me, at all.”

Of course, not everything that is ego alien is due to alternate personalities. For example, the obsessions and compulsions of a person with OCD (obsessive-compulsive disorder) are egodystonic, but most people diagnosed as having OCD do not have multiple personality (although there has been at least one case in which an initial diagnosis of OCD was later changed to multiple personality).

So if a person had a history of multiple “I don’t know where that came from” experiences, I would not be certain that the person had multiple personality, but I would certainly consider the possibility.

For prior discussions in regard to various writers and related ideas, search “self-contradiction” and “possession.”