A comparison of two psychological treatments for bulimia nervosa: implications for models of maintenance.

In an effort to elucidate the role of cognitive factors in the maintenance of bulimia nervosa, the efficacy of two psychological treatments was examined in a randomised control trial: cognitive behaviour therapy in the absence of explicit exposure instructions was compared with exposure and response prevention treatment in the absence of cognitive restructuring procedures. In the short term both treatments were successful at effecting substantial improvement in both the specific and the non-specific psychopathology of the disorder. However, at a one year follow up, whilst improvements were well maintained for those who had received the cognitive-behavioural treatment, virtually all of those who had responded to the purely behavioural treatment had relapsed. This provides some support for the cognitive model of the maintenance of bulimia nervosa. Nevertheless, the two treatment groups could not be distinguished on post-treatment measures of cognitive disturbance and neither was it the case that residual levels of cognitive disturbance, as assessed, predicted relapse. This may suggest that the level at which the necessary cognitive change takes place may not be accessible by conventional assessment procedures.