Personality patterns in patients with myotonic dystrophy

Background: Myotonic dystrophy (DM) is a multisystemic disease. The central nervous system is affected by cognitive, affective, and personality disturbances. A characteristic behavior was noted from the first clinical descriptions, but no definitive conclusions have been drawn despite extensive debate. As DM is a genetic disease of well-defined abnormality, it may be a good model for understanding the relative contributions of nature and nurture in the building of personality traits. Objective: To investigate the possibility that there is a personality pattern that is characteristic of patients with DM. Subjects and Methods: The personalities of 15 adult (age range, 20-53 years) patients with DM with no, or minimal, muscle weakness were studied by means of the International Personality Disorder Examination. The results were compared with those from 14 matched healthy subjects (age range, 20-54 years) and 12 patients (age range, 22-50 years) with a mild form of facioscapulohumeral dystrophy. Setting: The Department of Neuromuscular Diseases, Hopital de la Salpetriere, Paris, France. Results: Patients with DM exhibited a homogeneous personality profile, with statistically significant differences (P<.005) for avoidant, obsessive-compulsive, passive-aggressive, and schizotypic traits. In both groups of controls, the personality profiles were extremely heterogeneous. Personality disorders (avoidant personality) were found in 4 of 15 patients with DM. Conclusions: The findings of this study suggest that the personality pattern of patients with DM is related to their disease. Their personality disorders are not attributable to their adjustment to a disabling condition. By contrast, among the patients with DM, the high incidence of avoidant personality, a phenotype poorly represented in the general population, supports the idea that it is the expression of a primary phenomenon related to a genetic mutation.