Nonorganic chronic headache is a common, challenging presentation in clinical practice. The aim of this study was to investigate the frequency of associated psychiatric psychopathology, personality disorders, or traits. In addition, the study attempted to investigate possible relationships of nonorganic chronic headache with alexithymia, locus of control, and pain perception. Psychiatric pathology, personality traits, and pain profiles were examined in 100 randomized patients with chronic headache lacking an obvious organic basis, and they were compared with 100 Ss, 50 with headache of a known organic cause and 50 healthy controls, by using structured clinical interviews. Somatoform pain disorder was diagnosed in 43% of the nonorganic and 20% of the organic headache group. Nine percent of the former group had major depression, 16% had dysthymia, and 8% had both. In the organic group, 56% had no psychiatric disorder and 20% had somatoform pain disorder. 77% of the patients in the nonorganic pain group had personality disorders compared with 24% of the organic headache patients. The study sample was more alexithymic than the other groups and had a culturally influenced locus of control.