Traumatic brain injury is the leading cause of disability in people under 40, severely disabling 150-200 people per million annually. Neuropsychiatric sequelae outstrip the neurophysical (such as ataxia or incontinence) as the major cause of disability. Problems with memory, attention, executive function, behavioural control, and regulation of mood, associated with injury to the frontal and temporal lobes, are particularly troublesome.

The vast majority of recovery after traumatic brain injury takes place in the two years after injury; after this the brain injured patient faces an uncertain future. In some patients further improvement is seen even as late as 5-10 years after injury. Thus some long term studies, unfortunately often weakened by low rates of follow-up, show surprisingly good outcomes.1 New-combe found that veterans who had had a head injury in the second world war showed no evidence of deterioration many years after injury.^w1 This might …