To compare ego defense mechanisms in adolescents with anorexia nervosa and other major psychiatric disorders, to defenses in healthy adolescents.

Thirty-seven patients with anorexia nervosa, 30 with major depressive disorder, 20 with obsessive-compulsive disorder, 53 with borderline personality disorder, 60 with schizophrenia, and 81 healthy controls were assessed with Pfeffer's Ego Defense Scale.

Regression, denial, projection, repression, introjection, and total defenses were common to all psychiatric patients and distinguished them from normal adolescents. In addition to these defenses, anorectic patients also used intellectualization more frequently than normal adolescents and psychiatric patients. They used sublimation more than other psychiatric patients. Patients with disorders, apart from obsessive-compulsive disorder, that are considered to be often comorbid with anorexia did not have different defense than schizophrenic patients.

Anorectic adolescents overutilize relatively more mature defenses than do psychiatrically ill adolescents, and they overutilize immature defenses compared with normal adolescents. This combination of mature and immature defenses may be related to the uniquely heterogeneous ego functioning seen in anorectic patients, and it may provide insight into the nature of the psychopathology of anorexia nervosa. It also could have important psychotherapeutic and prognostic value.