The benefit of reconsidering the boundaries in therapy for someone with an eating disorder is straightforward. The feedback from patients and evidence of its success are both very strong.
The boundaries in therapy were originally aimed at creating an environment in which the patient can objectively analyze and understand emotions and behavior. The relatively blank slate of the therapist acts like a mirror for the patient to better understand herself. The therapist works hard to reflect observations of the patient to help her make better sense of her inner self and interpersonal relationships.
Eating disorders are almost like insidious viruses in the mind. The illness starts at a formative age when identity is still malleable and confounding. The physical manifestations of the eating disorder generate a lot of response, often positive. This feedback loop tends to reinforce the thought process of the illness and cements it as a core part of identity.
By the time the person realizes the destructive presence of the illness, the thoughts are such a central part of the self that separating the two feels like an exercise in futility.
If the therapist erects firm boundaries and invites the patient to look inward, therapy just reflects back the obvious: the patient has an eating disorder that is a strong part of identity.
Effective therapy for eating disorders needs to break down typical boundaries and create a much more genuine relationship between therapist and patient. The goal is for that connection to be established between the therapist and the healthy part of the patient, the non-eating disorder part.
This bond, a critical one to learn for recovery, allows the patient to see that powerful relationships outside the purview of the eating disorder, increase the impetus, over time, to challenge the thoughts and do the work to stick with recovery.
Patients often say that the effect of this therapy is that they feel seen or heard without the eating disorder symptoms. That feeling of recognition can serve as a strong motivation to believe true recovery is possible, a necessary component of any effective treatment.
The most significant downside of these boundaries is for the patient either slipping or in a relapse. That person has lost all connection with the healthy part of herself, the part not connected to the eating disorder. It makes it feel like any genuine connection in therapy is lost, and that loss causes enormous pain. Returning to recovery will quickly bring back the real relationship in therapy but can still take work to mend.