Substantial studies have investigated homogeneity of psychological distress level among cancer patients by using cross-sectional and longitudinal study design. Nonetheless, as proposed by Bonnano (2004), heterogeneity characteristics of psychological distress following stressful event could not be neglected and he further suggested that the majority of individuals were resilient in response to stressful events. To test this postulation, recent studies employed growth mixture modelling method to examine the heterogeneity characteristics of psychological distress trajectory among cancer patients. Furthermore, identifying relevant factors differentiate the psychological distress trajectories is an integral part for developing effective interventions for cancer patients in dealing with illness demands. However, only a few studies have examined these issues among Chinese colorectal cancer patients, a second most common cancer in Hong Kong. Therefore, it is of important need to address this knowledge gap. This study had two major aims: 1) to explore the patterns of psychological distress among Chinese patients with colorectal cancer from shortly after diagnosis but before surgery (i.e. 1-day prior operation) to 1-year post-surgery and to testify Bonnano’s theory on resilience; 2) to identify the effects of cancer-related intrusive thoughts, physical symptom intrusiveness and dispositional optimism on differentiating psychological distress trajectories. A total of 246 Chinese patients with colorectal cancer were recruited for the current study. Altogether, 5 consecutive face-to-face interviews were conducted on one day prior to surgery (baseline), 1-, 4-, 8- and 12-month post-surgery (T2-T5). Patients’ psychological distress (i.e. anxiety and depression), physical symptom intrusiveness, cancer-related intrusive thoughts, dispositional optimism, demographic and medical information were assessed by a standardised questionnaire with valid and reliable psychometric instruments. Growth mixture modelling was used to estimate and specify the psychological distress trajectories. Multinomial logistic regression was adopted to assess the proposed factors in relation to differentiate the trajectory patterns. Growth mixture modelling suggested three distinct trajectories were identified for both anxiety and depression model. The majority of patients with colorectal cancer were identified as resilient (i.e. maintaining low and stable distress level across time) for both models (anxiety: 82.3%, depression: 82.7%). Additionally, for anxiety trajectory model, the remaining 12.3% and 5.4% of patients were classified as moderately-low anxiety group (i.e. maintaining moderate to low distress level) and increasing anxiety group (i.e. increased from moderate level of distress at initial to subsequently high distress level) respectively. For depression trajectory model, the remaining 12.6% and 4.7% of the patients were grouped as delayed depression (i.e. delayed level of distress over time) and recovery depression (i.e. recovered from high distress level to low across time). Multinomial logistic regression showed that cancer-related negative intrusive thoughts, physical symptom intrusiveness and dispositional optimism were significant factors to differentiate anxiety and depression trajectories respectively. This study highlighted the heterogeneous feature of psychological distress among Chinese patients with colorectal cancer. Physical symptom intrusiveness, cancer-related negative intrusive thoughts and dispositional optimism played important role on predicting cancer patient’s psychological distress respectively. Nonetheless, further investigations are much needed to clarify the underlying mechanism. / published_or_final_version / Public Health / Master / Master of Philosophy