A self-guided digital mental health intervention for Syrian refugees in Germany and Sweden: effects from two pragmatic randomized controlled trials

BACKGROUND: Syrian refugees across diverse host countries, including high-income European countries, face increased mental health needs. Digital interventions can scale support, but global scalability limits human guidance and contextual adaptations. We evaluated the effectiveness of a potentially scalable digital intervention (Step-by-Step; SbS) with minimal contact-on-demand (COD) in reducing psychological distress and functional impairment among Syrian refugees in Germany and Sweden. These trials were conducted in parallel with SbS studies in Egypt and Lebanon, using the same content to test broader contextual applicability without further adaptations. METHODS: Separate two-arm pragmatic RCTs were conducted in Germany (N = 559) and Sweden (N = 184) with Syrians screening positive for elevated distress (K10 > 15) and impaired functioning (WHODAS 2.0 > 16). Participants were randomized to SbS (five sessions) + care-as-usual (CAU) or CAU-only. Primary outcomes were psychological distress (HSCL-25) and functioning (WHODAS 2.0) at 3-month follow-up. Secondary outcomes were PTSD symptoms (PCL-5 short) and self-defined problems (PSYCHLOPS). Intention-to-treat (ITT) analyses were run separately by trial. Exploratory per-protocol analyses combined datasets. RESULTS: ITT analyses showed no statistically significant time × condition effects for any primary or secondary outcome in both trials. Dropout was high (Germany: 86.3%; Sweden: 82.1%). In per-protocol analyses (participants completing ≥ 4 of 5 sessions), the SbS + CAU arm showed significantly lower standardized mean scores at 3 months for psychological distress (HSCL-25; Hedges' g = 0.31; p = .03) and PTSD symptoms (PCL-5 short; Hedges' g = 0.27; p < .05). COD use was low (Germany: 15.1%; Sweden: 8.4%), leaving the intervention effectively unguided for most participants. CONCLUSIONS: While limiting guidance and contextual tailoring can enhance scalability across borders, digital interventions may struggle with engagement, adherence, and contextual relevance. In high-income settings, an unguided approach for refugees may not work, showing that prioritizing scalability could potentially compromise clinical impact in this population. Some level of human guidance may be necessary to balance scalability and effectiveness, and it remains unclear how minimal that guidance can be without compromising outcomes. TRIAL REGISTRATION: German Register for Clinical Studies (Germany: DRKS00022143-registered June 29th, 2020, and Sweden: DRKS00022144-registered July 1st, 2020).