Objective A significant proportion (15–30%) of patients with mild traumatic brain injury (MTBI) are at risk of developing postconcussional syndrome (PCS). The aim of this study was to investigate the contributions of cognitive, emotional, behavioural and social factors to the development of PCS and identify early predictors.

Methods A prospective cohort design was employed. 126 MTBI patients completed baseline questionnaire assessments within 2 weeks of the injury and 107 completed follow-up questionnaire assessments at 3 and 6 months. A series of self-report measures were used to assess cognitive, behavioural and emotional responses to MTBI. The primary outcome was the ICD-10 diagnosis for PCS. Demographic and clinical characteristic variables were compared between PCS cases and non-cases using independent sample t tests and χ² tests. Individual and multivariate logistic regression analyses were used to detect predictors of PCS.

Results Of 107 MTBI patients, 24 (22%) met the criteria for PCS at 3 months and 22 (21%) at 6 months. Individual logistic regression analysis indicated that negative MTBI perceptions, stress, anxiety, depression and all-or-nothing behaviour were associated with the risk of PCS. Multivariate analysis revealed that all-or-nothing behaviour was the key predictor for the onset of PCS at 3 months while negative MTBI perceptions predicted PCS at 6 months.

Conclusions The study provides good support for the proposed cognitive behavioural model. Patients' perceptions of their head injury and their behavioural responses play important roles in the development of PCS, indicating that cognitive and behavioural factors may be potential targets for early preventive interventions.