Thirteen patients with depression following minor head injury were matched with 13 functional depressives. Both groups were indistinguishable psychopathologically. Five of the functional group had a family history of affective disorder and none of the head-injury group had such a history. Both groups were treated with amitriptyline, beginning with 100 mg daily, increasing to a maximum of 250 mg/d. There were significant differences in response between the 2 groups, with only 4 of the head-injury patients improving. Our preliminary results suggest that this condition is relatively resistant to tricyclic therapy.