ICD-11 complex post-traumatic stress disorder and psychiatric comorbidity among UK Armed Forces veterans in Northern Ireland: a latent class analysis.

There is evidence to suggest that the experience of complex post-traumatic stress disorder (C-PTSD) may be commonly associated with elevated risk for several mental ill-health comorbidities. The current study seeks to contribute to the growing literature on C-PTSD comorbidity by examining the relationship between C-PTSD and other mental health disorders in a UK Armed Forces veteran sample. This study used data from the Northern Ireland Veterans' Health and Wellbeing Study (NIVHWS). The effective sample consisted of 638 veterans (90.0% male). Tetrachoric correlations examined the relationship between C-PTSD caseness and other mental health outcomes. Latent class analysis was then conducted, determining the optimal number and nature of classes in the sample in relation to C-PTSD, depression, anxiety, and suicidality. C-PTSD caseness (i.e. probable diagnosis) was found to be significantly associated with positive caseness of depression, anxiety, and suicidality. Overall, four latent classes emerged, with each of these classes characterized by varying degrees of comorbidity: a 'Resilient/Low Comorbidity' class, a 'Lifetime Suicidal' class, a 'PTSD Polymorbid' class, and a 'C-PTSD Polymorbid' class. These findings support and extend previous results indicating the highly comorbid nature of C-PTSD. C-PTSD may be considered a highly polymorbid condition, increasing the risk for multiple mental health pathologies concurrently.