A book has been published that combines recent recommended treatments for DID with the treatment of IFS, or Internal Family System. The title is Trauma and Dissociation: Informed Internal Family System: How to Successfully Treat Complex PTSD and Dissociative Disorders by Joanne H. Twombly. (ISBN 9798887591353)
I've watched for over a decade on this board as various members express frustration, confusion or exhaustion as their therapist applies IFS terms and theory directly to us, the client, without making sufficient allowance for the dissociation or for alters/parts. IFS posits that the "mind is made up of relatively discrete subpersonalities, each with it's own unique viewpoint and qualities."
Sounds kind of like DID, right? It should. The theory owe a lot of its development to an awareness of DID. However, confusion, frustration or even damage to a client with DID can occur when a therapist assumes these subpersonalities exist for someone with DID in similar ways for someone who is not dissociative. The subpersonalities described by the theory are NOT identical to alters or dissociated parts. Trying to make the theory line up with parts/alters of an individual often doesn't work.
Assuming the existence of "the Self" in a DID system can be extremely confusing and misleading. When I met briefly with two therapists who were IFS practitioners I felt many of us getting upset. One therapist was making assumptions about us that were way oversimplifying, applying labels that didn't fit. Therapists may identify alters using categories that are key to internal family systems thinking -- exiles, firefighters and managers. These don't necessarily match up at all with the role, purpose or origin of DID parts and alters.
If you hear your therapist using the three terms or if you know they use IFS in their treatment, I suggest recommending they read this book to learn how best to treat you.
In my opinion, the danger of applying IFS too rigidly, as the danger of doing that with almost any one theoretical approach to DID, is oversimplification -- making assumptions that just don't fit the specific person, who experienced a unique array of traumas and/or neglect. So my opinion of IFS is admittedly cautious, sometimes negative. Not so for Twombly's book, which is more positive.
This book clarifies for both the therapist and client how to take advantage of some IFS principles and techniques without ignoring the difference between dissociative minds and non-dissociative minds. Twombly is a DID specialist with decades of experience and is one of the contributors to the Guidelines for Treating Dissociative Identity Disorder in Adults, Third Revision. She gives seminars on all of the above, as well as on using EMDR in the treatment of DID.
I sat in on a workshop she gave at a DID conference in Boston a few year ago and I liked her expressed mission of educating therapists who treat -- and, really, mis-treat -- DID. Like a handful of other long-term DID specialists, she's authored articles and book chapters on DID. I think she also consults with therapists who are fairly new to treating DID.