Background: Stress-induced dissociative states involving analgesia are a common feature of borderline personality disorder (BPD) and posttraumatic stress disorder (PTSD). Our aim was to investigate the psychologic, somatosensory (pain sensitivity) and neural correlates of dissociative states in patients with these disorders. Methods: We included 15 women with BPD who were not taking medication; 10 of these women had comorbid PTSD. While undergoing functional magnetic resonance imaging at 1.5 Tesla, participants were exposed to a script describing a personalized dissociation-inducing situation and a personalized script describing a neutral situation. We assessed dissociative psychopathology and pain sensitivity. Results: Dissociative psychopathology scores were significantly higher and pain sensitivity was lower after the dissociation-inducing script was read compared with the neutral script. The blood oxygen level-dependent (BOLD) signal was significantly increased in the left inferior frontal gyrus (Brodmann area [BA] 9) during the presentation of the dissociationinducing script. Regression analyses revealed positive correlations between BOLD signal and dissociative psychopathology in the left superior frontal gyrus (BA 6) and negative correlations in the right middle (BA 21) and inferior temporal gyrus (BA 20). In the subgroup of participants with comorbid PTSD, we also found increased activity in the left cingulate gyrus (BA 32) during script-driven imagery-induced dissociation, a positive correlation between dissociation scores and activity in the right and left insula (BA 13) and a negative correlation in the right parahippocampal gyrus (BA 35). Limitations: The main limitation of this pilot study is the absence of a control group. Therefore, the results may also reflect the neural correlates of non-BPD/PTSD specific dissociative states or the neural correlates of emotionally stressful or "loaded" memories. Another limitation is the uncorrected statistical level of the functional magnetic resonance imaging results. Conclusion: Our results showed that the script-driven imagery method is capable of inducing dissociative states in participants with BPD with and without comorbid PTSD. These states were characterized by reduced pain sensitivity and a fronto limbic activation pattern, which resembles the findings in participants with PTSD while in dissociative states.

This review provides an overview of the most recent neuroimaging findings in borderline personality disorder. The contributions of the structural and functional imaging studies of the past 3 years are presented to help us better understand this severe psychiatric disorder. There are three domains of functional imaging findings: 1) affective dysregulation; 2) the complex of dissociation, self-injurious behavior, and pain processing; and 3) social interaction. Knowledge of the neurobiological basis of borderline personality disorder has grown considerably. Therefore, these findings convey a good impression of the current findings from neuroimaging research in this disorder and also of the necessary next steps with regard to content and methodology.

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