Attention deficit hyperactivity disorder symptoms and response inhibition after closed head injury in children: do preinjury behavior and injury severity predict outcome?

We examined the effect of closed head injury (CHI) on the development of symptoms of secondary attention deficit hyperactivity disorder (SADHD), emotional disturbance, and impaired response inhibition. We also investigated the relation of developmental and recovery variables to SADHD symptoms and inhibition. Participants were 200 children aged 5-17 years, 137 children who had CHI, and 63 children with no history of CHI served as controls. We assessed preinjury behavior problems, head injury variables (severity, age at time of injury, time since injury), postinjury SADHD, and anxiety symptoms at least 2 years following the head injury. Response inhibition was measured with the stop-signal task. CHI predicted the development of SADHD symptoms and anxiety with more severe injury predicting more severe outcomes. Only the combination of severe CHI and a high level of SADHD symptoms predicted poor response inhibition. Postinjury anxiety was not associated with poor inhibition. The consequences of CHI did not vary with age at injury or time since injury, but poorer outcome was predicted by preinjury behavior problems. CHI in children leads to SADHD symptoms and anxiety even after taking preinjury disturbance into account. Poor response inhibition is a consequence of CHI but only when the CHI is severe and the child manifests high levels of SADHD symptoms.