Background There is a need to establish how long term outcome evolves after head injury (HI) and factors related to this, to inform opportunities for intervention.

Objective To determine late outcome in adults 12–14 years after hospital admission for HI and to examine relationships between injury, early and late factors, and disability.

Methods A prospective cohort with HI, whose outcome was reported previously at 1 and 5–7 years after injury, were followed up after 12–14 years. Participants were assessed using structured and validated measures of disability (Glasgow Outcome Scale-Extended), psychological well being, alcohol use and health status.

Results Of 219 survivors followed-up at 5–7 years, 34 (15.5%) had died by 12–14 years. Disability remained common in survivors at 12–14 years (51%), as found at 1 and 5–7 years (53%). For those disabled at 1 year, outcome was poor, with 80% dead or disabled at 12–14 years. Older age at injury, a premorbid history of brain illness or physical disability and post-injury low self-esteem and stress were associated with disability at 12–14 years. Disability changed between 5–7 and 12–14 years in 55% of survivors, improving in 23%. Late changes in disability between 5–7 and 12–14 years were associated with self-perceptions of locus of control as being ‘powerful others’ at 5–7 years.

Conclusions Disability is common 12–14 years after hospital admission with a HI. For some there is a dynamic process of change in disability over time that is associated with self-perceptions of control that could be a target for intervention based research.