OBJECTIVES: Improving mental illness (MI) & mental health services are a priority for Canadian health systems. Drug therapy can be a key component of managing mental illness, and a positive HTA reimbursement recommendation is most often necessary for public reimbursement of new therapies. This study investigated: 1) Trends in CADTH recommendations for mental health (MH) and non-mental health (NMH) drugs from 2012 onwards; 2) Key reasons for MH ‘Do Not List/Reimburse’ recommendations (DNLR); and 3) The rejection rate for MH products for CADTH compared with INESSS (Quebec), NICE (UK), PBAC (Australia), and SMC (Scotland).

METHODS: CADTH’s DNLR rate for MH and NMH products was compared from 2012 onwards, and Reasons for MH DNLRs were compiled. Recommendations for the same MH product/indication pairs were compared between CADTH and other HTA bodies.

RESULTS: MH drugs had a greater DNLR rate than NMH drugs (54% vs. 17%, p<0.001). Reasons for MH DNLRs frequently focused on uncertainty regarding clinical benefit. MH drug rejection rates from 2012 onwards for other HTA bodies were lower: INESSS (48%), NICE (25%), PBAC (44%), and SMC (15%); p<0.05 only versus SMC. CADTH aligned with INESSS for 46% (n= 13) of MH recommendations, NICE for 100% (n=3), PBAC for 70% (n=10), and SMC for 67% (n=6).

CONCLUSIONS: Overall, CADTH was significantly less likely to recommend reimbursement for MH drugs versus NMH drugs, primarily due to uncertainty regarding clinical benefit. There was a trend towards lower acceptance rates for MH drugs versus other HTA bodies (only the comparison with SMC was statistically significant). These trends have important implications regarding equity of access to novel treatments for patients in Canada with mental illness that deserve further study and discussion.