Purpose (1) To evaluate the effectiveness of personalised psychologically-informed physiotherapy in people with neck pain; (2) To explore the mediating role of changes in illness perceptions.

Method In this replicated single-case study, 14 patients with non-specific neck pain at risk for chronicity received a personalised intervention addressing unhelpful illness perceptions and dysfunctional movement behaviour, according to principles of cognitive functional therapy. Outcomes included the mediating role of illness perceptions on overall effect, function, pain intensity and self-efficacy. Linear mixed models were used to analyse the data.

Results Repeated measurements (14-20 per patient), including a 3-months follow-up, showed a gradual improvement during and/or after psychologically-informed physiotherapy for overall effect, function, pain and to a lesser extent self-efficacy. Changes in each of the illness perception dimensions showed a mediation effect on overall effect, function and pain. When combining the dimensions “consequences,” “personal control,” “identity,” “concern” and “emotional response,” changes in illness perceptions explained approximately 35% of the improvement in overall effect.

Conclusion Addressing unhelpful illness perceptions appears valuable in the management of patients with chronic or recurrent non-specific neck pain. Intervention effects extended beyond the treatment period, indicating that patients’ improved understanding of their health condition continued to have a positive impact.