Mental illness and participation in colorectal cancer screening: a scoping review

INTRODUCTION: Compared with the background population, persons with mental illness have increased colorectal cancer (CRC) mortality. Screening has the potential to alleviate the increased cancer mortality due to mental illness, but the extent to which persons with mental illness participate in CRC screening programs is uncertain. This scoping review aims to summarize the literature on CRC screening participation among persons with mental illness. MATERIALS AND METHODS: We searched four databases (PubMed, PsychInfo, Embase, and the Cochrane Library) to identify published literature on mental illness and participation in CRC screening programs. We included full-text papers available in English, published before February 2021, and excluded papers on dementia, intellectual disabilities, and developmental disabilities. RESULTS: In total, we included 17 studies and categorized the findings according to severity of mental illness. Across varying study designs, the studies found that persons with severe mental illness, e.g. schizophrenia, participate less in CRC screening compared with the background population. The results were ambiguous for common mental illness, such as depression and anxiety. In general, studies were small or lacked comparison groups and the estimates were imprecise. CONCLUSION: This is the first scoping review to evaluate participation in CRC screening programs among persons with mental illness. Overall, the existing literature lacks high quality evidence from large population-based studies and comparison groups based on organized screening programs.