Objective To use population-based data to follow youth who have or have not sustained a concussion to determine the risk of adverse psychosocial outcomes.

Design Retrospective population-based cohort.

Setting Province of Manitoba, Canada.

Participants Manitoba youth (10–18 years) between 2000–2005. Concussion was identified from provincial administrative health data. For each concussion, five non-concussion controls were selected from the general population and matched on neighborhood and age. All youth were followed for 10–15 years (3279 concussed and 16,395 non-concussed).

Interventions (or Assessment of Risk Factors) Concussion status

Outcome Measures New onset psychiatric, social, and judicial outcomes were extracted using datasets linked to the population data repository. Hazard ratios (95% confidence intervals) were estimated using Cox proportional hazard models and adjusted for sex, urban vs rural, parental psychiatric history, father present, and socioeconomic status.

Main Results Concussed youth who had an increased risk of attempting or completing suicide (1.38; 1.01–1.87), developing attention deficit hyperactivity disorder (1.39; 1.15–1.68), developing a substance abuse disorder (1.43; 1.23–1.66), being accused of a crime (1.29; 1.20–1.37), and having allegations of child maltreatment within their household (2.56; 1.50–4.36) compared to no concussion. There was a significant interaction by sex for the risk of developing mood disorders (boys: 1.14; 1.02–1.26 vs girls: 1.41; 1.26–1.57) for concussed youth versus no concussion.

Conclusions Concussions were associated with an increased risk for adverse psychosocial outcomes. Future directions include identifying risk factors for adverse psychosocial outcomes so interventions can be developed.