Heterogeneity of personality traits in massive obesity and outcome prediction of bariatric surgery.

The search for heterogeneity of personality characteristics amongst the massively obese is extended to a larger sample (n = 215) of both males (n = 83) and females (n = 132). The Minnesota Multiphasic Personality Inventory standard scales serve as the data base for a cluster analysis which has yielded four clusters: cluster 1 (n = 36) where all scales fell well within normal limits; cluster 2 (n = 112) was coded as 3-1 and was also within normal limits; cluster 3 (n = 44) was coded as spike 4; and cluster 4 (n = 23) was coded as 2-1-7-3-8-4. Cluster membership was not related to surgeons' four-year follow-up overall outcome rating. Discriminant function analysis yielded two variables (patient age and MMPI scale 1 T-score) which were significant predictors of subsequent outcome. The results suggest that there is heterogeneity of personality traits among the massively obese and offer encouragement to the search for variables that are even more effective predictors of the outcome of bariatric surgery.