[Trauma-focused and personality disorder treatment for posttraumatic stress disorder and comorbid cluster C personality disorder].

Background: Posttraumatic stress disorder (PTSD) is associated with high rates of avoidant, dependent and obsessive-compulsive personality disorders (cluster C-PD). It is unknown whether concurrent treatment for PTSD and comorbid cluster C-PD leads to superior treatment effects, compared to standalone trauma-focused treatment.

Aim: To test the efficacy of adding 52-58 sessions of PD treatment (group schema therapy; GST) to 12-18 sessions of individual trauma-focused treatment (imagery rescripting; ImRs).

Method: 130 adult outpatients were randomized to receive either ImRs or ImRs+GST. The main outcome was PTSD severity one year after start of treatment (CAPS-5). Secondary outcomes were cluster C-PD, psychiatric symptoms, quality of life, functioning, treatment response, remission, and dropout.

Results: At 12 months, there were large decreases in PTSD severity (d = 2,4), PD symptoms and all other secondary outcomes. There were no significant differences between conditions.

Conclusion: Large effects were observed in both treatment arms. The results suggests that trauma focused treatment is the preferred primary treatment in patients presenting with PTSD and comorbid cluster C-PD, after which more intensive psychotherapy aimed at the personality disorder may be considered in the case of residual personality disorder symptoms.