Patient Expectations in the Treatment of Depression: The Role of Outcome Expectancy in Therapeutic Change across Psychotherapy versus Pharmacotherapy

The present study extended previous research on outcome expectancy by exploring its temporal dynamics, as well its relation to depression improvement in two different treatment modalities. A sample of 104 patients with depression were randomized to receive either cognitive behavioural therapy (CBT) or pharmacotherapy for 16 weeks. Outcome expectancy was measured throughout treatment using the Depression Change Expectancy Scale (DCES), a measure comprising two subscales assessing pessimistic versus optimistic expectancies. Results corroborated the role of pre-treatment expectancy on treatment response in CBT. Moreover, associations between mid-treatment expectancy and treatment response were seen in pharmacotherapy. Notably, the associative patterns between expectancy and depression in CBT differed as a function of expectancy valence (i.e., pessimistic versus optimistic). Results support a possible mediational role of expectancy across different treatments for MDD. Future studies incorporating larger sample sizes and more frequent assessments of during-treatment expectancy will be needed to validate these results.M.A