Background Colorectal cancer (CRC) has implications for patients’ psychological well-being. Understanding the impact of psychological factors like anxiety and depression on patients’ treatment journey is crucial for optimizing care outcomes. This study assessed how initial anxiety and depression levels predict post-operative psychological experiences.

Methods 233 CRC patients were followed from diagnosis to 12 months post-surgery. The Hospital Anxiety and Depression Scale (HADS) was administered at each time point. Anxiety and depression scores were categorised as ‘Normal’ and ‘At risk’ (score >8). Baseline demographic and clinical data were extracted from electronic medical records. Generalised estimating equations (GEE) models analysed how baseline anxiety and depression scores and other post-operative factors predicted post-operative anxiety and depression scores over time.

Results Baseline anxiety and depression scores significantly predicted anxiety and depression scores over time (p<0.01). Patients considered ‘At risk’ for depression and anxiety at baseline consistently reported higher scores throughout the year compared to the ‘Normal’ group, particularly in the first three months post-surgery. Stoma formation predicted higher anxiety and depression (p<0.05) levels, notably in the first-month post-surgery. Receiving chemotherapy predicted higher anxiety (p<0.05) but not depression scores.

Conclusions Patients considered ‘At risk’ for depression and anxiety, especially those receiving stoma or chemotherapy, require enhanced support during the initial three months of treatment. Future studies should explore how stoma and chemotherapy influence anxiety and depression levels in both groups.