MMPI-2 scores in the outcome prediction of gastric bypass surgery

A psychological assessment is critical for morbidly obese patients seeking Roux-en-Y gastric bypass (RYGBP) surgery. The Minnesota Multiphasic Personality Inventory (MMPI) has been widely used in past psychological studies of bariatric surgery patients, but, to date, there is no published research on the more recent version of the MMPI, the Minnesota Multiphasic Personality Inventory-2 (MMPI2), and its relation to RYGBP outcome. This investigation was designed to evaluate the predictive validity of the MMPI-2 with respect to outcome of RYGBP for morbid obesity.

The research involved a retrospective analysis of MMPI-2 scores of 2 groups of patients 1 year following RYGBP: 1). those who lost >or= 50% of their excess weight and 2). those who lost <50% of their excess weight. Subjects were 52 morbidly obese patients (mean age 44 years, mean BMI 56 kg/m2). The measurement of psychological variables consisted of the MMPI-2 scores of 3 validity scales, 10 clinical scales, and 3 Content Scales, and BMI.

Those who lost <50% excess weight scored significantly higher than those who lost >50% excess weight on the F,Hysteria, Paranoia, and Health Concerns scales of the MMPI-2, and significantly lower on the Masculinity-femininity scale. Stepwise regression analysis found that a combination of the Health Concerns and Masculinity-femininity scales was the most accurate predictor model for 1-year post-surgery weight loss.

A standard personality measure, the MMPI-2, appears to be associated with weight loss outcome 1 year after RYGBP. Psychological traits such as anxiety and excessive health concerns are likely to influence bariatric surgical outcome.