Positive psychology interventions in patients with medical illness: What predicts improvement in psychological state?

Positive psychology interventions (PPIs) have been shown to promote wellbeing in individuals with medical illness, although it is still unknown whether certain patient characteristics make participants more likely to benefit from such interventions. The present study tested whether, using individual patient data across five published PPI studies (three single-arm proof-of-concept trials, one non-randomized controlled trial, and one randomized controlled trial) in medically-ill persons, sociodemographic or psychological factors predicted subsequent change in wellbeing. In 208 participants, lower baseline psychological wellbeing and optimism, and higher symptoms of depression and anxiety were associated with greater improvement in psychological symptoms during the PPI. Other factors were unrelated to symptom changes. In a sub-analysis of controlled studies, there were no group differences in the relationship between baseline factors and changes in wellbeing from pre- to post-intervention. Findings suggest that patients with more severe psychiatric and/or medical comorbidity are no less likely to benefit from a PPI compared to those with higher levels of health, even though these programs do not directly target psychological distress. PPIs may be widely applicable to medical patients, with lower psychological wellbeing a potential predictor of increased benefit