Perhaps the most bizarre example of compartmentalization is the psychopathology referred to as multiple personality disorder, in which one body seems to be carrying around a number of distinct personalities. Some of them are sometimes cognizant of the existence of some of the others. The drama within this person becomes “Who is in control?” Interestingly, one “personality” rarely holds another in high esteem. The one constant in all cases of multiple personality seems to be that the person was severely abused and traumatized as a young child. The severity of abuse was so extreme that the adult or adults involved would be classified as deranged.
The resulting fragmentation of personality into distinct and separate voices with no overall integration can act as a self-protective survival strategy. It’s the way people with multiple personalities learned to safely express different parts of themselves without having to be responsible for any of them. In order to have such extreme fragmentation, the messages given about how to be (that is, how to be “good”) had to be not only contradictory, but impossible to achieve. There was nothing these people could do to satisfy their abusers.
We look at multiple personalities as yet another way of giving up on trying to be “good” – in this case by letting go of the integrating aspect of the mind that remembers, identifies with, and evaluates what the organism does. Although compartmentalization to this degree is relatively rare, the phenomenon itself is not. It is most likely to occur [when] people internalize values they cannot live up to. 
- Kramer, Joel and Diana Alstad. The Guru Papers: Masks of Authoritarian Power. Frog Books,1993. 203. [↩]