I looked up a review of MPD/DID treatment practices, and their effects. I’m skipping the extensive and disturbing description of the lengths practitioners go to in order to elicit alters, but it includes things like spending 4-8 hours in therapy without breaks attempting to elicit personalities (i.e., you don’t get to go home till you show me a personality), and taking momentary silence or a glance around the room to indicate a switch in personalities.
Selections from the article:
This proliferation of alters is typically accompanied by clinical deterioration that is often quite marked. In one investigation, more than 8 of 10 patients “developed florid posttraumatic stress disorder during [DID therapy]”; the authors commented that this result is typical (6, p 361). Hallucinations, increasing discomfort, and severe dysphoria often cause patients to be in states of chronic crisis for long periods of time after DID treatment begins (9,11,52–54).
Moreover, suicide attempts may occur in the weeks following the diagnosis: Fetkewicz and associates showed that, after the diagnosis had been made, MPD-diagnosed patients attempted suicide more frequently than age- and sex-matched patients suffering from major depressive disorder (55). In another study, 4 of 5 MPD patients improved dramatically when they were rediagnosed and treated in more conventional ways (56).
Such deterioration should surprise no one, given the treatment practices that leading DID proponents recommend. These proponents believe that successful treatment requires DID patients to search their memories for each supposed trauma and then to abreact (that is, experience in therapy) the memories and associated emotions (1,11,57). Such searches frequently consume hours of each day, and the abreactions are extremely draining (58,59). Patients thus sink ever more deeply into a swamp of ruminations about past mistreatment, abuse, and trauma.
We don’t have a lot of research on this, unfortunately. It would be nice to have more. Part of it is for the reason the article talks about – in practice MPD/DID is often specified in ways that dodge testable definitions, which sets things up so that you can’t ever find out that a diagnosis is wrong, regardless of whether it is. Part is because it’s fringe, which is unfortunate because it’s also important.
This is in agreement with other research I’ve read – eliciting alters is a good way to get someone’s mental health to deteriorate. I’ve heard this cited as a reason that a lot of North American MPD clinics have closed, but I don’t know if that’s really the reason; my guess would actually be that they closed because they weren’t getting new patients, not because they were serving their old patients poorly.
Here is part 1 of the article above (with a historical review of MPD).