Association between baseline dissociation levels and stress-induced state dissociation in patients with posttraumatic-stress disorder, borderline personality disorder, and major depressive disorder.

Introduction: Dissociative symptoms are highly prevalent in patients with trauma-related disorders such as borderline personality disorder (BPD) and posttraumatic-stress disorder (PTSD), and also occur in patients with depressive disorders. Acute dissociative states are theorized to be stress-related, and some individuals experience recurring patterns of dissociation. The relationship between the intensity of dissociative episodes (trait-like dissociation) and acute dissociative states, however, is incompletely understood. In the present study, we investigated how levels of baseline (trait-like) dissociation relate to changes in dissociative states during a laboratory stress induction.

Methods: Our female sample comprised 65 patients with BPD and/or PTSD, 84 patients with major depressive disorder (MDD) and 44 non-clinical controls (NCC). Baseline dissociation was assessed at the start of the study using the Dissociation Tension Scale past week version (DSS-7). All participants underwent the Trier Social Stress Test (TSST) and a placebo version (P-TSST). Before and after the TSST or P-TSST, state dissociation was assessed using the Dissociation Tension Scale acute (DSS-4). We used structural equation models to estimate changes in state dissociation items (somatoform dissociation, derealization, depersonalization, analgesia), and to test whether these changes relate to levels of baseline dissociation.

Results: We found significant increases in all state dissociation items in response to the TSST in patients with BPD and/or PTSD and patients with MDD, but not in NCCs. Increases in somatoform dissociation and derealization during the TSST were significantly related to higher levels of baseline dissociation in patients with BPD and/or PTSD, but not in patients with MDD or NCCs. Results indicate no significant changes in state dissociation during the P-TSST.

Conclusion: Our results replicate earlier findings that patients with BPD and/or PTSD report higher levels of stress-related state dissociation than NCC and extend them to patients with MDD. In addition, our findings indicate that baseline levels of dissociation relate to stress-induced changes in state dissociation among patients with BPD and PTSD, but not patients with MDD. In clinical applications, measures of baseline dissociation could be used to facilitate the prediction and treatment of stress-related dissociative states in patients with BPD and/or PTSD.