Interrelations between ego functions and personality traits: their relation to psychotherapy outcome.

Ninety consecutive admissions to a large outpatient clinic of a municipal hospital completed two self-report questionnaires: the Self-Evaluation Questionnaire (SEQ) which consists of four 10-item scales that assessed four areas of ego functioning; and the 89-item Personality Profile Index (PPI) that provided measures of eight dimensions of personality traits and also a measure of conflict. Results indicated that the four measures of ego functioning had good internal consistency, and three of the four ego functions had a highly similar pattern of relations to the personality trait dimensions and to the conflict measure. It thus appears that each set of constructs amplifies and sheds light on the other. Two of the ego function measures were significant predictors of psychotherapy outcome. They correlated highly with one another and also with a third measure of ego functioning. This fact, together with the similarity of their correlations with the personality traits, suggests that these ego functions represent different aspects of an underlying construct that could be called Ego Strength. Therefore, combining the three ego functions into a 30-item Ego Strength measure could provide an even more sensitive predictor of therapy outcome and a useful new instrument for psychotherapy research.