Illness and treatment beliefs as predictors of rehabilitation outcome in patients with mental disorders.

Objective: Illness and treatment beliefs are important predictors of health outcomes. However, little is known about their impact on outcomes in psychosomatic rehabilitation. Thus, the aim of this study was to investigate the impact of illness and rehabilitation-related treatment beliefs in patients with mental disorders attending psychosomatic rehabilitation.

Methods: We applied a longitudinal study with two measurement points (before rehabilitation; end of rehabilitation) in a psychosomatic rehabilitation clinic. Patients with mood disorders, anxiety or fear-related disorders, stress associated disorders or bodily distress disorders were included. Using regression models, we analysed whether illness and rehabilitation-related treatment beliefs predicted the rehabilitation outcome (operationalised through "Health-49"). Illness beliefs were assessed using the IPQ-R, while treatment beliefs were assessed using the RTBQ-Psych. Analyses were conducted separately for patients with a F3 and F4 diagnosis in accordance with the ICD-10.

Results: N = 239 patients were included, sample size per regression model ranged between n = 48 and n = 85. Mean age was 50.8 years, and n = 120 were female. Initial symptom burden was the strongest predictor in all models with 12% to 64% explained variance. Concerning illness beliefs, perceived consequences, treatment control, and cyclic timeline were negatively linked to the outcome, whereas coherence and emotional representations were shown to be positive predictors. Regarding treatment beliefs, expectations towards treatment results were positively and concerns were negatively associated predictors.

Conclusion: Illness and treatment beliefs are predictors of the rehabilitation outcome. Patients´ beliefs might therefore be good starting points for interventions in the context of rehabilitation.