To assess the clinical and personality characteristics of patients with chronic daily headache before and after treatment, 20 patients were examined and the Minnesota Multiphasic Personality Inventory (MMPI [Italian 356-item abbreviated version]) and the Strait and Trait Anxiety Index 1,2 (STAI) administered. There were two groups: group 1 (n = 6), with a "conversion V" configuration (with elevation of hypochondria and hysteria scales, the depression scale being somewhat lower); and group 2 (n = 13) with elevation of depression and of other MMPI scales. One patient had no scale elevation. STAI 1,2 scores were high in both groups. Several psychosomatic symptoms and some migraine features were present in almost all patients. Occurrence, severity, and duration of headache were recorded regularly and the MMPI and the STAI administered again after treatment. Improvement of headaches and a decrease of several MMPI and STAI 2 scores were observed. However, 12 of 20 patients showed a conversion V configuration after treatment. It is concluded that chronic daily headache was transformed migraine in most cases and was accompanied by anxiety levels in all patients and hysteric traits in some. With time, these patients may develop a depressive disorder. After treatment, hysterical traits are still present at a lower level in those showing these traits before treatment and may be unmasked in those that had depression.