Internal-external control and weight loss in the obese: predictive and discriminant validity and some possible clinical implications.

It is argued that the locus of control dimension relates to various aspects of noncompliance with health-related advice. Among a sample (N = 131) of obese females following a behavioral weight loss program a measure of perceived personal control significantly predicted outcome. Internals and externals did not differ in cumulative weight loss early in the program, but did so from 8 weeks on; internals achieved greater mean weight loss. The internal control orientation was associated with higher extraversion and self-acceptance, but neither of these other variables correlated with weight loss. Clinical and theoretical implications of the interaction with time are discussed.