Mind the gap: a nested randomised pilot study of culturally inclusive, internet-delivered prolonged exposure for PTSD among immigrants

<b>Background:</b> PTSD is disproportionately prevalent among immigrants in Sweden, yet access to evidence-based treatments remains limited, especially for those facing language barriers. Internet-delivered prolonged exposure (I-PE) may help overcome these challenges, but its feasibility and effectiveness in diverse populations remain underexplored.<b>Objective:</b> This study evaluated the feasibility, acceptability, and preliminary effects of a culturally inclusive, therapist-guided I-PE programme in easy-to-read English for immigrants with PTSD.<b>Method</b>: A nested pilot study within an ongoing RCT randomised 30 participants to I-PE or a waitlist control. The intervention incorporated simplified language, diverse visual representations, and a user-friendly platform. Feasibility outcomes included recruitment, adherence, and retention. Acceptability was assessed through satisfaction, adverse effects, and cultural appropriateness, while preliminary efficacy was evaluated via PTSD symptom severity and secondary measures of depression.<b>Results:</b> Recruitment was completed in six weeks, with moderate to high retention. Adherence was strong, with 63% completing at least five I-PE modules. Participants rated the intervention as highly acceptable, with no major cultural barriers. The easy-to-read English format was well received, with no reported linguistic accessibility issues. No serious adverse events were reported. PTSD symptoms significantly decreased in the I-PE group (Cohen's <i>d</i> = 1.45; <i>p</i> < .001), with moderate reductions in depression (Cohen's <i>d</i> = .80; <i>p</i> < .01).<b>Conclusions:</b> The findings support the feasibility and acceptability of a culturally inclusive, therapist-guided I-PE programme for PTSD among immigrants. The participants perceived the I-PE as helpful, trustworthy, and easy to use, with no suggestions for further cultural modifications or reports of cultural inappropriateness. However, the sample's relatively high English proficiency and education may limit generalizability to other groups who have migrated to Sweden. A full-scale randomised controlled trial is needed to assess clinical and cost-effectiveness, as well as implementation across more diverse immigrant populations.<b>Trial registration:</b> ClinicalTrials.gov identifier: NCT06193161..