About two-thirds of patients who complete courses of cognitive behavioral therapy (CBT) report noticeably improved symptoms. Until recently, less was known about how CBT affects temperament and character.

The ability to identify certain characteristics of individual patients that might predict treatment outcome could influence the choice of treatment and help predict its effectiveness. Since personality characteristics can change during treatment, they might also be especially valuable as measures of treatment effectiveness and indicators of therapeutic change, according to researchers at Virginia Commonwealth University, Richmond, VA, and Christchurch School of Medicine, Christchurch, New Zealand (Comprehensive Psychiatry 2002;43:182).

A personality trait that suggests better outcome

One of the Virginia researchers, Dr. Charles B. Anderson, noted that in the current study and earlier studies, the personality trait of "self-directedness" was positively affected by CBT. This characteristic is measured by the Temperament and Character Inventory (TCI) and is defined as a developmental process that includes acceptance of responsibility for one's choices, identification of individually valued goals and purposes, resourcefulness, and self-acceptance

The authors' study involved a randomized clinical trial of 135 women, 17 to 45 years of age, with a current DSM-III-R diagnosis of BN. The study was designed to examine the additive effects of two forms of exposure with pre-response prevention to a core of CBT for treatment of BN. Trained clinical psychologists used a manual for the sessions. The treatment course included self-monitoring, psycho-education, identification of cues, challenging automatic thoughts, thought restructuring, chaining (learning related behaviors in which each response acts as a stimulus for the next response), and relapse prevention. Specific goals were outlined for each session clearly in the manuals and homework was assigned for each module. For the first 2 weeks, sessions were held twice a week, then weekly for 4 more weeks.

After this, participants were randomized to one of three groups: exposure with response prevention to pre-binge cues; exposure with response prevention to pre-purge cues; or relaxation training (controls). After the last treatment session, all the women underwent final post-treatment assessment with one of the principal investigators who were blinded to the treatment condition. The women were assessed with the same structured interview for bulimia nervosa as on admission, and were also evaluated with the Hamilton Depression Rating Scale and a semistructured measurement of bulimic symptoms.

There were no significant differences reported across the three behavioral treatments as to percentage of persons abstinent from bingeing or purging or mean frequency of bingeing and purging at the end of treatment.

Status after one year

Scores of self-directedness not only predicted treatment outcome for patients with BN but overall self-directness was improved with CBT in women with BN. The results of the study also indicated that the efficacy of CBT was particularly "robust," considering that 8 sessions of CBT plus 8 sessions of exposure or relaxation training appeared to have produced a significant change in self-directness. Thus, the authors believe that the portions of CBT that affect self-directness may hold promise for enhancing treatment of BN.