Distinct correlates of post-traumatic stress disorder and subthreshold post-traumatic stress disorder considering a broad range of adverse experiences.

Background: While not all trauma-exposed individuals develop post-traumatic stress disorder (PTSD), many experience severe and enduring emotional effects. In Singapore, no study has investigated the prevalence and correlates of subthreshold PTSD and PTSD using gold-standard clinical interviews.Objectives: This study was the first to examine the prevalence and correlates of PTSD, subthreshold PTSD, and correlates associated while exploring a broad range of adverse experiences, including Criterion A (e.g. physical and sexual abuse) and non-Criterion A (e.g. emotional abuse) events.Method: We recruited 500 outpatients, aged 21-65, with mood or schizophrenia spectrum disorders from Singapore's only tertiary psychiatric hospital. Self-report measures assessed emotion dysregulation, suppression, and total trauma events. Clinical interviews, like the Clinician-Administered PTSD Scale (CAPS-5), measured dissociation and PTSD, while the Brief Psychiatric Rating Scale measured negative affect. Among trauma-exposed individuals (n = 461), multinomial regression examined differences between subthreshold PTSD, PTSD and the no-PTSD reference group, with analyses conducted separately for Criterion A and non-Criterion A events.Results: In the overall sample, PTSD prevalence was 15.0% and subthreshold PTSD was 18.4% among individuals with an index event classified as Criterion A. PTSD following an index event classified as Criterion A was associated with a broader range of correlates than index events classified as non-Criterion A. Conversely, among individuals exposed to events classified as non-Criterion A, PTSD was primarily associated with emotional correlates when subthreshold PTSD was defined as 'two of four criteria.' PTSD is also associated with a broader set of correlates than subthreshold PTSD across exposure types and subthreshold PTSD definitions. Correlates of subthreshold PTSD vary depending on exposure type. Negative affect was most frequently associated with multiple definitions of subthreshold PTSD and PTSD across trauma types.Conclusion: Findings suggest distinct symptom profiles by trauma type and emphasise the clinical relevance of non-Criterion A events and subthreshold PTSD.