Neuropsychologic outcome at one-month postinjury was investigated in a group of 102 adult patients with head injury representing a broad spectrum of severity. A group of friends of the patients with head injury was selected for comparison purposes. A comprehensive battery of measures assessing various abilities determined the adequacy of neuropsychological functions. Results support the following conclusions: head injury is associated with early deficits observable on measures assessing a broad spectrum of functions, ranging from simple to complex and motoric to abstraction skills; use of appropriate control groups is essential for determining head injury related deficits; the degree of neuropsychologic deficits depends on the severity of head injury; and the severity indices of time to following commands and depth of coma relate more closely and systematically to adequacy of one-month neuropsychologic outcome than does retrospectively assessed posttraumatic amnesia.