Considerations regarding treatment efficiency, dissociative parts and dissociative amnesia for Huntjens et al.'s Schema Therapy for Dissociative Identity Disorder.

Dear Dr. Olff,

We concur with Huntjens, Rijkeboer, and Arnzt (2019) that the quantity and quality of dissociative identity disorder (DID) treatment research must become improved, and that multiple baseline single-case series (Schubert, 2011) constitutes a useful approach (Nijenhuis, 2015, 2017). They present schema therapy (ST) as an alternative for phase-oriented trauma treatment models (in short ‘POTT-models’) for DID. We appreciate their intention to study ST’s efficacy. However, (1) we do not agree with their comparison of ST and POTT-models; (2) their presentation of our dissociation theory (Nijenhuis, 2015, 2017; Van der Hart, Nijenhuis, & Steele, 2006) as a guide for POTT-models is inadequate; and (3) their review of experimental studies on dissociative amnesia could be more exhaustive.

#1. Huntjens et al. criticize POTT-models as ‘intensive and lengthy,’ whereas these models actually hold that treatment best proceeds as fast as possible and as slow as needed. The intensity and pace are dependent on contextual variables such as the patient’s and therapist’s power of action (Nijenhuis, 2017). Although the total length of therapy may differ, the proposed ST and POTT-models involve a comparable number of sessions. ST’s biweekly sessions may actually involve a more intensive approach than POTT’s common weekly sessions. This intensity could prove to be effective, but DID-therapy in natural settings is usually subject to practical and financial restrictions that preclude biweekly sessions. ST also impresses as a phase-oriented approach and several major interventions are quite similar. For example, in both approaches close attention is given to the function of aggressive and critical dissociative parts while pacing and validating their needs (Nijenhuis, 2017; Van der Hart et al., 2006).

#2. Huntjens et al. accept our view that dissociative parts of the personality involve their own first-person perspective, but erroneously state that in our view dissociative parts ‘involve discrete, personified behavioural states or “biopsychosocial action systems” that take “executive control of the person’s body and behaviour” … ’ (p. 9). What we (Nijenhuis, 2015, 2017; Van der Hart et al., 2006) actually say is that dissociative parts are overlapping in some but not other regards. They do not involve behavioural states but are subsystems of the personality with their own needs and related sensations, perceptions, affects, cognitions, and strivings. They are not action systems but are primarily affected, influenced or guided by particular (constellations of) action systems. There is a major difference between being affected by something (e.g., an action system) and being something.

#3. Huntjens et al. claim that experimental studies show intact inter-identity memory pathways. Although several studies did not find inter-identity amnesia for procedural memory or non-self-relevant adverse, emotional, and neutral stimuli, it is important to note that results are not fully consistent and that these studies did not use personalized self-relevant information (e.g., Reinders et al., 2016). Secondly, we do not hold that there must be dissociative identity-dependent recall for procedural memory or non-self-relevant adverse, emotional, and neutral stimuli. Thirdly, we have proposed that some dissociative identities referred to as apparently normal parts (ANPs: Van der Hart et al., 2006) may tend to mentally avoid traumatic memories, while others referred to as emotional parts (EPs: Van der Hart et al., 2006), may tend to relive traumatic memories as if they were present events. Huntjens et al.’s assertion of ‘intact memory pathways’ (p. 4) is at odds with this framework and some data suggesting that these dissociative identities may have very different, hypotheses-fitting and memory-dependent subjective, physiological and neurophysiological reactions to audiotaped descriptions of traumatizing events (e.g., Reinders, Willemsen, Vos, Den Boer, & Nijenhuis, 2012), as well as neurophysiological and behavioural reactions to subliminally presented neutral and angry faces (Schlumpf et al., 2013) and to rest-instructions (Schlumpf et al., 2014). Fourthly, results from studies that include DID patients who went through integrative therapeutic work and can alternate in a controlled fashion between some of their dissociative identities in experimental settings, may not be representative of naturally occurring dissociative amnesia. For example, inpatient POTT was associated with a reduction of negative dissociative symptoms including dissociative amnesia and normalization of functional EEG beta-band connectivity (Schlumpf, Nijenhuis, Klein, Jäncke, & Bachmann, 2019).

In all, we propose that ST is like the POTT-models and is intensive, lengthy and phase-oriented, that prototypical dissociative parts include their own biopsychosocial features, and that some experimental studies did find support for inter-identity amnesia. We therefore recommend that ST therapists take possible naturally occurring dissociative amnesia in DID into account.