Implementation and effectiveness of the WHO Self-Help Plus (SH+) intervention in the Gaza Strip: a prospective hybrid type 1 non-randomised study

Background Self Help Plus (SH+) is a WHO intervention that provides strategies for managing distress arising from adversity. In the Palestinian context, SH+ holds promise in supporting psychological well-being and mitigating the impact of trauma, with the critical challenge in adapting and scaling the intervention for feasible and sustainable delivery. Methods This is the piloting phase of a prospective hybrid type-1 non-randomised follow-up study investigating the implementability and effectiveness of SH+ in early 2023 in the Gaza Strip. Participants were recruited by the Gaza Community Mental Health Programme, which also facilitated the intervention. Assessments were conducted immediately before and one week after the intervention. Exposure to traumatic events was measured by the Gaza Trauma Checklist (GTC). Implementability was evaluated using the Feasibility of Intervention Measure, the Acceptability of Intervention Measure, and the Intervention Appropriateness Measure. Effectiveness was assessed using the Depression, Anxiety, and Stress Scale-21 items (DASS-21), the WHO-5 Well-being Index, and the WHO Disability Assessment Schedule (WHODAS 2.0)-12 items. After each session, the facilitators completed an online fidelity test for the intervention. Findings Of 177 eligible participants, 162 completed the pre-assessment, and 157 the post-assessment. Results indicated that 151 participants (96.16%) found SH+ acceptable, 131 (83.44%) appropriate, and 139 (88.45%) feasible. In terms of effectiveness measures, the estimated average psychological well-being score increased from 10.78 (SE = 0.42) to 17.69 (SE = 0.41), indicating a substantial enhancement in well-being. The disability scores were estimated to decrease, on average, from 22.70 (SE = 0.63) to 18.35 (SE = 0.53), and significant improvements were also observed across all DASS subscales, and in the global DASS score, with fitted model values declining from 58.97 (SE = 1.85) to 33.02 (SE = 1.71). Interpretation The pilot phase of the study shows that SH+ is a scalable psychological intervention for individuals exposed to trauma in the Gaza Strip. Conducting the implementation phase is needed to confirm the findings.