A study of personality subtypes in treatment seeking obese patients

Previous research has not been able to identify a distinct personality style that refers specifically to obese individuals. The purpose of this investigation was to explore whether different personality-based groups can be identified in obese individuals, as has been shown with eating disorder patients. Data were collected from 149 obese patients (BMI = 37.3, ± 6.4; 83% female) seeking dietary treatment and psychological support for their weight problems. Participants completed the Millon Clinical Multiaxial Inventory III (MCMI-III; Millon, 1997) and a battery of eight measures assessing psychological distress, mood states, eating behaviors, obesity-related quality of life, and interpersonal problems. The MCMI-III personality scales were cluster analysed to classify participants into personality subtypes. Three personality clusters were retained (externalizing, internalizing, high-functioning), and several differences in the validating variables emerged across the three personality subtypes. The internalizing group reported the greatest level of personality distress and an increased likelihood of poor psychosocial functioning and high eating behavior symptoms. Findings support the clinical utility of personality subtypes in obesity. Future work is needed to identify causal pathways between personality typologies and eating disorders in obese individuals.