I actually just quickly read through IFS and it looks like it's full of bullshit. Subpersonalities? Parts? This all sounds like Jungian archetypal wishy-washy psychobabble. I'm so glad that we are past the Jungian/Freudian era. They might have contributed largely to how we view psychology now but some of their understanding of psychology was way too entrenched in understanding the unconscious domain.
In terms of the self-harm, I do find that strange. I always thought that the self-harm tendencies is only associated with BPD.
Yes, I believe IFS is bullshit too. I mentioned it because I brought up the subject of how a certain treatment center I went to often over diagnosed DID. My experience at this treatment center, which is a eating disorders and trauma-based treatment center, actually nearly traumatized me.
While I was a patient there, I had little experience with therapy or treatment and so I didn't really understand why some things that happened there seemed really...WRONG...to me. The founders of the treatment center, particularly Mark Schwartz, were really odd...they dressed really funny and just did things that seemed unusual to me. I witnessed multiple patients constantly having "flashbacks" (they were totally faking it) and even claim that they had "trauma food" (food that reminds them of a trauma they have). I was pretty naive at the time, but I was smart enough to know that this was all bullshit. Anyway, my therapist tried IFS on me. I actually did give it a chance for maybe a week or so...but the way they talk in IFS makes patients sound like they are nuts and I didn't want to sound like that. For example, one patient there would sometimes start talking like a child and claim that this was her "child part."
After I discharged from the treatment center, the more time that passed where I was back out in the 'real world'...the more strange the treatment center seemed to me when I thought about it. I stayed in touch with some former patients, and many of them continued to go back inpatient at the treatment center. Many of these people that I personally know will tell you (and they really believe it) that not only did Mark diagnose them with DID, but their families were part of a satanic cult that ate babies. Soon I personally made a correlation between IFS and the misdiagnosis of DID. I can't say that IFS caused the diagnosis...but I can say that each person I know who was diagnosed with DID was an active participant in IFS therapy.
Furthermore, this was all broadcast in the media about a year and a half ago. Many patients came forward and sued Mark, claiming he had planted in them false memories (specifically about being in a satanic cult). I can give you some links if you want to read more about it.
With this experience I believe it gave me a new perspective on life, particularly what is healthy and what is not. The treatment center ironically felt very much like a cult...and I didn't really realize it until after I had been discharged for some time and 'snapped out of it.' So although it was a bad experience for me, it was also a good experience...because now I know both how good therapy can be and also how potentially damaging it can be.
Oh, and while self-harm is certainly associated with BPD, it is not always directly caused by it. One of my best friends is a recovered self-harmer...and she would have been considered 'hard core' (she has the scars to prove it). She is not diagnosed with BPD nor does she behave at all like someone with BPD. I have seen many self-harmers, both with and without the BPD diagnosis.
Here is a short article about the treatment center lawsuit, which also provides links to lawsuit cases:http://www.kmov.com/news/editors-pick/Castelwood-Treatment-Center-Lawsuits-178973201.html