OBJECTIVES: ACUDep, a randomized pragmatic trial, compared acupuncture, counselling, and usual care for relieving depression. Patient perceptions about the effectiveness of treatments may affect costs and health outcomes through compliance or a placebo effect. The objective of this study was to assess the cost-effectiveness for patient subgroups with different perceptions about treatment effect. METHODS:  ACUDep reported outcomes on costs and EQ-5D for up to 12 months for 755 patients. Patient perceptions about the effectiveness of each treatment was measured on a five-level likert scale. A binary variable was generated indicating if a patient had a positive opinion about the treatment, i.e. they thought the treatment would be fairly effective or very effective. A seemingly unrelated regression was used to estimate costs and QALYs with coefficients for treatment received, positive perception of each treatment and an interaction term between all coefficients. RESULTS: Most patients did not have a positive perception of any of the treatments, 31.3% responded very ineffective, fairly ineffective or can’t decide for their perception of effectiveness of all treatments. 5.7% of patients had a positive perception of all treatments. Using a threshold of £20,000 per QALY the cost-effective treatment varied depending on the expectation of treatment effectiveness. Acupuncture was the cost-effective treatment for patients that were not optimistic about any or all of the treatments. Counselling was the cost-effective treatment in the subgroups that thought only counselling would be effective, only acupuncture would be effective or either of them would be effective. Usual care was cost-effective in the patient populations that thought that only usual care would be effective or usual care and either acupuncture or counselling would be effective. CONCLUSIONS:  In this analysis patient perception does affect observed treatment outcomes and alters which treatment is cost-effective. Further consideration should be given to assessment of patient perceptions and there use in reimbursement decisions.