This dissertation, "A Prospective Study of Changes in Psychosocial Characteristics of Patients With Dentofacial Deformities After Corrective Surgery" by Ka-shing, Suen, 孫嘉誠, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Background: Jaw corrective surgery can cause significant psychosocial impacts on patients. This prospective study aimed to investigate the longitudinal changes of psychosocial characteristics of patients with dentofacial deformities after corrective surgery and the factors that predict the psychological resilience of Hong Kong Chinese undergoing this type of surgery. Materials and Methods: A prospective cohort study was carried out from 1st June 2011 to 31st December 2012 on Hong Kong Chinese patients, who had corrective surgery as treatment for their dentofacial deformities. Self-completed questionnaires, including Brief Symptom Inventory (BSI), Adult Trait Hope Scale (AHS), Hospital Anxiety and Depression Scale (HADS), Life Orientation Test (LOT), Social Avoidance and Distress Scale (SADS) and Satisfaction with Life Scale (SWLS), were administered to each patient at the surgical consent signing date (T1), one pre-operative day (T2), 1-2 post-operative week (T3) and 3rd post-operative month (T4). Psychological outcome trajectories were established using the BSI General Severity index (GSI) at T1, T3 and T4. Five patterns of outcome trajectories were created using specified outcome measures of psychological distress level, including chronic dysfunction, recovery, delayed dysfunction, resilience and others. They were then categorized into two patterns of outcome trajectories (resilience and non-resilience groups) for analysis. Independence sample t-test and logistic regression analyses were conducted to investigate the significance of life orientation level at baseline to predict resilience. Results: 67 participants (23 males, 44 females; mean age 25.6) were recruited in the study. Highest hope level and psychological distress level was noted pre-operatively at the surgical consent signing date. The levels then dropped post-operatively in the first 3 months. No statistically significant difference was noted on the depression and anxiety level, social avoidance and distress level, optimism level and life satisfaction level from pre-operative to post-operative stages. The proportion of the five patterns of outcome trajectories was chronic dysfunction (22.4%), recovery (7.5%), delayed dysfunction (3%), resilience (43.3%) and others (23.8%). The logistic regression analyses showed that the pre-operative baseline optimism level of LOT was a significant predictor on the resilience characteristic of a patient after orthognathic corrective surgery. Conclusion: Patients with dentofacial deformities have high level of hope and equally high level of psychological distress at the surgical consent stage of orthognathic surgery. Their psychological distress and hope levels tend to drop during the first three post-operative months. There is no expected peri-operative change on the depression and anxiety symptoms, social avoidance and distress, optimism level as well as life satisfaction level in these patients. Optimism level can predict the psychological resilience of a Hong Kong Chinese in going through orthognathic surgery. Brief Symptom Inventory (BSI) and Life Orientation Test (LOT) are recommended as preoperative psychological screening tools. DOI: 10.5353/th_b5063967 Subjects: Jaws - Abnormalities - Surgery - Psychological aspects