In Transactional Analysis terms dissociation can be diagrammed as such.
It is a split in the personality where the Free Child is split off. Of course the young child does this in childhood for a very good reason. It usually occurs in reaction to some traumatic event the child experienced. To cope it splits off the FC as a way of protecting it. The person then gets the sensation that it is not me being hurt but another self. An effective solution indeed. One knows this has happened when the client talks about self as ‘it’ or a part of them self that is ‘not me’.
Whilst this is a good solution in childhood if it remains into adulthood then it creates problems of its own. The solution then becomes the problem because it is not how humans function effectively. To function effectively one needs a least satisfactory connection to the FC.
How does one reconnect it? How does one remove the split in the personality and connect it up again. One way to do this is to remove the secret (assuming there is one. Sometimes there is and sometimes there is not).
If there has been some kind of trauma then not uncommonly the person has kept it a secret and told very few, especially if there has been some kind of sexual component. In individual therapy the client can eventually tell the therapist about it. This is good and can assist the remove the split in the personality. However group therapy can be particularly helpful here. Once the individual feels safe in the group then they are in a position to disclose the secret to a group of people.
If this is done then the Adult ego state and the Free Child know that others now know what happened at least in some degree. This confronts the personality. The split off Free Child now knows a group of others know what happened. This makes it harder, maybe even much harder, for the FC to pretend that it didn’t. Or, at the least, pretend that it didn’t happen to me. It is harder to maintain the split in the personality and the dissociation is treated.