Dropping out of treatment for obesity.

This study compared the pre-treatment characteristics of participants in three weight reduction programmes who either completed treatment or dropped out. The three programmes each lasted for 16 weeks, selected subjects on the same criteria, and offered the same dietary advice. The first two programmes were run by the same psychologist in the same community setting. In each study a different set of characteristics significantly separated completers from dropouts, and discriminant function analysis assessed how well this separation was achieved. The discriminant function from the first study correctly identified 75% of the subjects on which it was based. When applied to the second study it correctly identified 64% of subjects, showing limited generalisability. There were also significant differences between early dropouts and late drop-outs, but the nature of these varied between studies. In discussing the implications of these results it was argued that further research might more fruitfully focus on psychological processes involved in drop-out rather than continue to search for correlates of drop-out.