Prediction of the prognosis of somatoform disorders using the Minnesota Multiphasic Personality Inventory.

Background: Somatoform disorders are frequently resistant to treatment. This study aimed to determine the utility of the Minnesota Multifaceted Personality Inventory (MMPI) in predicting the prognosis of somatoform disorders.

Methods: Overall, 125 patients diagnosed with somatoform disorders between January 1, 2013 and December 31, 2017 in the psychiatric department of Fukushima Medical University Hospital were included. Patients with positive outcomes were identified based on a subjective estimation regarding (1) pain and (2) social functions, including activities of daily living. They were divided into the improved group (IG) and the non-improved group (NIG). Each factor was then descriptively compared between the two groups, and the sensitivity and specificity were determined.

Results: The NIG had significantly higher scores but only on the Hy scale. Thus, the optimal Hy scale cutoff score was calculated. The cutoff point was 73.5, with a sensitivity of 55.7% and a specificity of 71.7%.

Conclusion: An MMPI Hy scale score higher than a cutoff value of 73.5 predicts a poor response to conventional supportive psychotherapy or drug therapy in patients with somatoform disorders. This cutoff point may be used as an important index for selecting treatment for somatoform disorders.