The committee concludes, on the basis of its evaluation, that there is sufficient evidence of an association between TBI and subsequent development of aggressive behaviors. Additional evidence that aggression is associated with TBI primarily when frontal cortical lesions are sustained is consistent with a large literature associating frontal lobe damage with loss of behavioral control.

The committee concludes, on the basis of its evaluation, that there is limited/suggestive evidence of an association between TBI and decreased drug and alcohol use, as compared with preinjury levels, in the 1–3-year period following the TBI.

The committee concludes, on the basis of its evaluation, that there is limited/suggestive evidence of an association between moderate or severe TBI and psychosis. However, even if the TBI is severe, the psychosis does not appear during the first post-TBI year, but rather, becomes apparent in the second and third post-TBI years.