Previous research has suggested that patients with amyotrophic lateral sclerosis (ALS) demonstrate similar psychological characteristics that distinguish them from the medically ill populations, and that these findings may bear etiologic and prognostic importance. In this report, a larger sample was studied and the prior findings were not replicated. Specifically, ALS patients were not found to have a more internal locus of control, or to use denial as a defense more than a group of patients with inoperable neoplastic disease. Although dysphoria was frequently found in ALS patients, only 22% demonstrated clinical depressive syndromes.