Changes in Defense Mechanism Functioning During Group Therapy for Binge-Eating Disorder.

Objective: This study examined change in defensive mechanism functioning during group psychodynamic interpersonal psychotherapy (GPIP) for women with binge-eating disorder (BED).

Procedure: Women with BED (N = 85) received 16 weeks of GPIP. Five group therapy sessions (sessions 1, 3, 8, 12, and 16) from each of the 12 groups were video recorded and transcribed. Participants were rated on an observer-based measure of defensive functioning, the Defense Mechanism Rating Scale (DMRS). Symptom outcomes were assessed pre- and posttreatment.

Results: Overall defensive functioning (ODF) scores improved significantly during group treatment, with specific defense level improvements in high adaptive, major image distorting, and action defenses. The linear increase in ODF mediated a decrease in binge-eating episodes and depressive symptoms. Reverse mediation was also noted. A cubic growth curve best modeled ODF data such that ODF improved in the early stage, followed by a slower rate of improvement in the middle stage, and a further increase in rate of improvement at the end of treatment.

Discussion: Change in defense mechanism functioning may be an important aspect of group psychotherapy that is related to improved symptoms for women with BED who receive GPIP. The cubic trend that represented nonlinear growth in ODF is consistent with psychodynamic theory and a stage model of psychotherapy.