18 The Measurement of Ego Defenses in Clinical Research

Among the more important contributions of psychoanalysis to personality theory and to the theory of psychological adaptation is the concept of ego defenses. The term "defense mechanism" first appeared in Anna Freud's The Ego and the Mechanisms of Defense (1936). This work described 10 methods of functioning used by the ego to ward off dangerous drives or wishes that would lead to painful feelings of anxiety, depression, or shame. Since that time, there has been general agreement that the defenses may be triggered by both internal and external stressors: that is, by both internalized prohibitions on the one hand and external reality on the other. There has also been substantial agreement on a number of aspects or facets of defense mechanisms: (a) they are the major means that the ego uses to manage instinct and affect and forestall potential conflict; (b) they are unconscious; (c) although a patient may be charac­ terized by his or her most dominant defense, each patient uses several defenses; (d) the defenses are dynamic and reversible; and (e) they may be adaptive as well as pathological (Freud, 1936; Perry & Vaillant, 1990).