Process evaluation of a hybrid effectiveness-implementation, pragmatic, cluster randomised controlled trial (IMPULSE) to improve psychosocial treatment of patients with psychotic-spectrum disorders in Southeast Europe

TL;DR

The IMPULSE trial evaluated a digital psychosocial intervention for psychosis in Southeast Europe, finding it improved quality of life and was generally well accepted by clinicians and patients.

Contribution

This study provides insights into the contextual factors affecting the delivery and sustainability of a digital psychosocial intervention for psychosis in low-resource settings.

Findings

DIALOG+ improved patients' quality of life after four sessions.

Moderate to high acceptability and high fidelity of the intervention were observed.

Contextual barriers like resource limitations did not impair outcomes but could affect long-term sustainability.

Abstract

The IMPULSE trial investigated the effectiveness and implementation of a digital psychosocial intervention (DIALOG+) for people with psychosis in five Southeast European countries. DIALOG+ significantly improved patients’ quality of life after four treatment sessions. The process evaluation reported here aimed to assess contextual influences on intervention delivery during the trial, to explain the trial findings and generate hypotheses about mechanisms of action by exploring acceptability from the perspectives of clinicians who delivered it and trial participants who received it, and fidelity (was the intervention delivered and received as planned?).

A mixed-methods process evaluation was conducted in accordance with the published protocol, guided by theoretical frameworks and the Medical Research Council’s guidance for complex interventions. To explore the role of context, data were analysed about the participating services, policy documents, and from focus groups with key stakeholders. Semi-structured interviews with clinicians and patients were conducted to explore acceptability. Process data (format and content of sessions) were analysed to assess intervention fidelity. Data analysis included descriptive methods, framework and content analysis, and triangulation.

Several attributes of context related to health services, including resource limitations, funding priorities, reliance on paper records and lack of community support, potentially negatively impacted DIALOG+ acceptability, fidelity and outcomes. Contextual enablers were also identified, including an appetite for change among key stakeholders that can help overcome contextual barriers. Acceptability of the psychosocial intervention was moderate to high and fidelity was high.

Intervention acceptability is likely to have played a key role in ensuring high fidelity, which in turn likely contributed to the intervention’s positive impact on patients’ quality of life. The high fidelity confirms that the IMPULSE trial findings provide a valid assessment of the intervention as designed. While the identified contextual barriers appear not to have impaired intervention fidelity, acceptability and outcomes, they could pose challenges to the long-term sustainability of the intervention.

Retrospectively registered on 29 March 2021, ISRCTN11913964

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