A rational basis for the psychopharmacologic management of behavioral disturbances after head trauma has been presented that is predicated on research in neurotransmitter changes that evolve subsequent to head trauma. The paucity of human studies in this area mandates the use of experimental models and evidence garnered from provocative challenges to suggest the underlying neurotransmitter profile in various behavioral abnormalities. Multiple neurotransmitter circuits exist that provide parallel, duplicate, and redundant systems for these behaviors. Certainly, alternative explanations could be offered for the examples cited above. Furthermore, measurement of neurotransmitter metabolite concentration in cerebrospinal fluid does not allow specific inferences to be made regarding topographic correlation and neurotransmitter function. Nor does it afford assessment of regional differences in psychotropic influence on neurotransmitter receptors. New imaging techniques (eg, positron emission tomography) will certainly aid in this determination. Current investigations, however, support the concept that neurotransmitter changes do occur after head injury, that these alterations exist during the time that "recovery" occurs, and that psychotropic agents influence this recovery process. Further research is needed to clarify neurotransmitter changes after head injury and to identify psychotropic intervention strategies that facilitate the recovery process.