Efficacy and effectiveness of psychological interventions for symptoms of complex PTSD in adults

The notion of complex posttraumatic stress disorder (CPTSD) is a longstanding yet contentious one: it has only recently been included as a diagnostic entity in its own right in the most recent version of the International Classification of Diseases (ICD-11: World Health Organization, 2018), and, after considerable debate, was not incorporated into the latest version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5: American Psychiatric Association, 2013). As such, the evidence base for how best to treat difficulties associated with complex trauma remains patchy. Further, most studies and meta-analyses to date have focused on highly controlled research trials across quite disparate populations, so our understanding of which interventions may be effective to the majority of clients seeking help for difficulties associated with CPTSD in “real-world” clinical practice (namely, those whose complex trauma originated in childhood), remains very limited. Chapter one of this thesis presents the results of a meta-analysis of the efficacy and effectiveness of psychological interventions for adult survivors of complex, childhood trauma, considering both randomized, controlled trials and non-RCTs. This meta-analysis showed that many interventions are effective in reducing symptoms of PTSD in this population; uncontrolled effect sizes (pre- to post- treatment) and controlled effect sizes (treatment versus control group measures at post-treatment) were generally largest for trauma-focused and “phase based” treatments compared to those aimed at initial safety and stabilization. Uncontrolled effect sizes were generally larger for RCTs (d = 1.02) compared with uncontrolled trials (d = 0.7). However, very few studies examined the effects of treatment on additional symptoms of complex PTSD (emotion dysregulation, negative self-concept, and interpersonal functioning), or more general measures of distress or functioning, which may arguably be of greater importance to many people seeking help with their difficulties. Chapter two presents the findings of a large-scale (n = 634) “real-world” study of outcomes associated with a safety and stabilization group intervention, “Survive and Thrive”, for women survivors of complex trauma as implemented in routine clinical care within two NHS Adult Mental Health services. This study found that Survive and Thrive appears to be acceptable, safe, and effective in reducing overall psychological distress and symptoms of PTSD, depression, and anxiety, with pre- to post-treatment effect sizes ranging from 0.5 – 0.81 (Cohen’s d) and proportions of participants achieving clinically significant improvements in symptoms ranging from 23 – 40% - at least, among those who complete treatment. However, the lack of a control group and high drop-out rate (46%) means that these preliminary findings are likely over-estimates of overall effectiveness and acceptability for the population of treatment-seeking women as a whole and must therefore be treated with caution. We hope the findings will contribute to the evidence base for psychological interventions for complex PTSD, ultimately allowing clients greater choice of evidence-based treatments for their longstanding and debilitating difficulties