Abstract
Background
Individuals with psychosis and comorbid posttraumatic stress disorder (PTSD) typically present with more severe forms of illness. Subthreshold posttraumatic stress symptoms (PTSS) are also likely to cause significant distress. There is a need to enhance screening processes for distressing PTSS to encourage appropriate referral to specialized services. The PTSD checklist for DSM-5 (PCL-5) is a widely used self-report to assess PTSS, though there is concern regarding its validity for use in psychosis. If people scoring in the severe PTSS range on the PCL-5 also present with clinical profiles similar to those typically meeting diagnosis for PTSD, it will justify considering a broader range of PTSS and support the use of the PCL-5 as a brief screener. A severe range will arguably capture a wider array of individuals, including those with subthreshold PTSS who also likely require trauma-focused intervention.
Methods
One hundred and two individuals with psychosis completed the PCL-5 and a battery of clinical scales as part of an intake evaluation following referral for psychological follow-up at a clinic specializing in psychosocial interventions for psychosis. Prevalence and type of DSM-5 criterion A event were explored in conjunction with PTSS severity and referral-type. Pearson correlations identified clinical variables associated with PCL-5 total scores and were subsequently entered into a multivariate analysis of variance (MANOVA) with dichotomized PTSS severity categories (low, moderate, severe). Post hoc analyses explored significant interactions.
Results
Of the 102 participants, 21.6% reported no prior trauma and 14.7% reported non-valid events. Sixty-five participants were included in the analysis; 6.2% of which were referred for trauma. 81.5% reported criterion A events, 10.8% reported psychosis-related events, and 7.7% did not disclose an event. PCL-5 scores were dichotomized using the 33rd and 66th percentiles, translating into low (≤ 24), moderate (25–47), and severe (≥48) groups. Delusion severity and subjective stress, anxiety, depression, social anxiety, quality of life (QoL), and wellbeing were entered into a one-way MANOVA with PTSS severity groups. Significant main effects surviving Bonferroni correction emerged for all variables except delusion severity (F(2,40) = 3.06, p = .058) and wellbeing (F(2,56) = 1.50, p =.233). Stress (F(2,62) = 7.37, p = .001) was higher in the severe (M = 13.13, SD = 5.18) versus low group (M = 7.05, SD = 4.40, p = .001). Anxiety (F(2,62) = 8.02, p = .001) was also higher in the severe (M = 12.30, SD = 5.07) compared to low group (M = 5.85, SD = 5.06, p = .000), and depression (F(2,62) = 5.37, p = .007) was additionally higher in the severe (M = 12.61, SD = 5.73) compared to low group (M = 7.20, SD = 4.97, p = .005). Finally, social anxiety (F(2,58) = 4.25, p = .026.) was higher in the severe (M = 7.76, SD = 3.58) versus low group (M = 4.68, SD = 3.68, p = .029), while QoL (F(2,58) = 3.47, p = .038) was lower in the severe (M = 49.95, SD = 10.99) compared to low group (M = 58.95, SD = 13.76, p = .037).
Discussion
Due to a relatively high number of invalid questionnaires (14.7%), service users should likely complete the PCL-5 in the presence of a health-care practitioner. Findings suggest inadequate referral rates for specialized services when they may indeed benefit the service-user. Severe PTSS was associated with increased symptoms of subjective anxiety, depression, stress, social anxiety, and decreased QoL, regardless of whether diagnostic criteria for PTSD was met. A severe PTSS category likely captures a broader range of individuals requiring specialized intervention and speaks to an important need to both facilitate and increase referral rate for trauma-focused therapy.
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