Personality characteristics in obesity: relation of MMPI profile and age of onset of obesity to success in weight reduction.

A group of 142 obese subjects was seen in an obesity clinic over a 2-year period. Of these, 116 had assessment of personality factors by the Minnesota Multiphasic Personality Inventory (MMPI), and 71 were followed for periods of 4 to 28 months in order to determine success at weight reduction by means of a conventional dietary regimen. The MMPI profiles of the obese subjects were compared to those of a general medical population of 50,000 patients seen in the Department of Internal Medicine at the Mayo Clinic. Obese male subjects had significantly higher scores on the F and MA scales. Obese female subjects had significantly higher scores on the F, PD, PA, SC, and MA scales, and a significantly lower score on the Q scale than the reference population. Even though these findings show that certain personality traits as measured by the MMPI may occur more frequently in obese persons, the individual MMPI profile codes point out the presence of diverse behavior patterns among obese persons rather than a single personality pattern characteristic of obesity. There were no apparent differences in the success in achieving a loss of 10% or more of initial weight among the male and female obese subjects having normal or abnormal MMPI profiles. Obese subjects having onset of obesity before age 12 years were slightly more successful in weight reduction than those whose obesity began later than this, but the differences were not statistically significant for either the male or female subjects.