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Boon 1999). However, they also note that there are differences between genuine and imitated DID and that there is no evidence that DID can (sub-) consciously be created by sociocultural factors (Gleaves 1996). Even if DID symptoms can be created iatrogenically or enacted (Spanos 1994) this does not demonstrate that genuine trauma-related DID does not exist (Elzinga, Van Dyck & Spinhoven 1998).
To date, the fantasy model has hardly been tested in studies involving DID patients (cf. (Van Heugten-van der Kloet et al. 2014)), and evidence that the complex phenomenology and psychobiology of DID can be created and sustained over time by these factors is lacking (Gleaves 1996, Brown, Frischholz & Schefin 1999, Xiao et al. 2006, Loewenstein 2007). The model mainly relies on studies with nonclinical samples regarding fantasy proneness, suggestibility, and memory, and cover only a small subset of the many studies on DID and traumatic dissociation (Loewenstein 2007). Despite this lack of empirical support, the fantasy model of DID is influential in contemporary psychiatry and there have been proposals to prevent the inclusion of DID in the DSM-5 (Gharaibeh, Merskey 2009). Although proponents of the model acknowledge that “most individuals with DID exhibit signs and symptoms of psychopathology and experience intense subjective distress” (Lilienfeld, Lynn 2003) (p.131), they believe these problems should be attributed to other disorders such as bipolar disorder, somatization disorder, and primarily, borderline and hysterical personality disorder (as described in Van der Hart, Nijenhuis 2009). Given these largely contradicting views, it seems to be of major importance to further study dissociative identity disorder, testing both models. In line with this, Brand et al. (2012) and, more recently Lanius (2015), specified the importance of conducting more neurobiological research.
This thesis aims to explore the etiology of DID in a design that acknowledges both the trauma and fantasy model. Moving beyond these positions, the hypothesis is tested whether DID has a unique pattern in brain structure and function when compared with control groups. Specifically, by identifying personality state differences in functional brain mechanisms as well as several psychological measures, results can further inform holders of both views about the etiology of DID and contribute to achieving consensus regarding diagnosis and treatment. In the past decades, research on the effects of trauma and mechanisms of recovery has evolved in various different directions. Despite these advances, countless individuals affected by traumatic stress still do
GENERAL INTRODUCTION
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