Investigating complex PTSD for understanding the consequences of trauma in a homeless sample

© 2017 Dr. Renee Michelle ArmstrongBackground: The International Classification of Diseases (ICD)-11 that is due for release in 2018 will introduce revised Posttraumatic Stress Disorder (PTSD) criteria as well as a new diagnosis of Complex PTSD. Criteria for this diagnosis of Complex PTSD has been under development, with considerable debate and revision of proposed criteria to this point. This study aimed to test the proposed ICD-11 criteria for PTSD and Complex PTSD in a sample of people who have experienced homelessness. Objective: This study investigated the fit of the ICD-11 Complex PTSD construct with mental health symptoms as reported by a sample of people who have experienced homelessness. This population was chosen to investigate the construct based on previous literature and clinical experience, suggesting that the experience of homelessness is largely synonymous with significant histories of trauma and associated mental health difficulties. Method: Two studies were conducted. First, a pilot study of semi-structured interviews were completed with individuals (N = 20) known to have a history of homelessness and trauma exposure. Findings were used to inform the second study: a cross-sectional empirical investigation of trauma exposure, related symptoms and comorbid mental disorders. Participants (N = 206) were service users who attended homeless support agencies in Melbourne, Australia. Latent Class Analysis (LCA) was used to investigate ICD-11 diagnostic groups in the sample. Results: The sample experienced very high levels of trauma exposure with the majority experiencing childhood abuse and neglect. Four distinct classes of participants emerged in relation to the potential to meet the proposed diagnosis: Class 1, ‘LCA Complex PTSD’ (n=119, 58%), Class 2, ‘LCA no diagnosis’ (n= 34, 16%); Class 3, ‘LCA PTSD’ (n=23, 11%) and finally Class 4, ‘LCA affect, social and self difficulties’ (n= 28, 14%). While those with an ICD-11 Complex PTSD diagnoses fell into the LCA Complex PTSD class, so also did those with an ICD-11 PTSD diagnosis. Conclusions: Our findings provide support for the proposed distinction between Complex PTSD and PTSD. The sample used in this study, of people experiencing homelessness, may have impacted on our findings given they were a highly exposed trauma sample