Self-help interventions for persistent physical symptoms: a systematic review of behaviour change components and their potential effects.

Persistent physical symptoms (PPS) remain a challenge in the healthcare system due to time-constrained consultations, uncertainty and limited specialised care capacity. Self-help interventions may be a cost-effective way to widen the access to treatment. As a foundation for future interventions, we aimed to describe intervention components and their potential effects in self-help interventions for PPS. A systematic literature search was made in PubMed, EMBASE, PsycINFO and CENTRAL. Fifty-one randomised controlled trials were included. Interventions were coded for effect on outcomes (standardised mean difference ≥0.2) related to symptom burden, anxiety, depression, quality of life, healthcare utilisation and sickness absence. The Behaviour Change Technique (BCT) Taxonomy v1 was used to code intervention components. An index of potential was calculated for each BCT within an outcome category. Each BCT was assessed as 'potentially effective' or 'not effective' based on a two-sided test for binomial random variables. Sixteen BCTs showed potential effect as treatment components. These BCTs represented the themes: goals and planning, feedback and monitoring, shaping knowledge, natural consequences, comparison of behaviour, associations, repetition and substitution, regulation, antecedents and identity. The results suggest that specific BCTs should be included in new PPS self-help interventions aiming to improve the patients' physical and mental health.