The role of agitation as a prognostic indicator of outcome in 26 patients with severe traumatic closed head injury was studied to explore haloperidol effects on the outcome of rehabilitation treatment. The incidence and degree of agitation and post-traumatic amnesia (PTA) in brain-injured patients undergoing comprehensive inpatient rehabilitation were also studied. Variables measured included length of coma, PTA, rehabilitation admission and discharge functional status, and CT scan results. Of the 26 patients, 25 were agitated after emerging from coma and 11 required intervention with haloperidol. Treated and nontreated patients were compared statistically. No differences were found between groups as to demographics, length of coma, and most importantly, in success of rehabilitation outcome. The duration of PTA was significantly longer in the treated group.