Prominent psychiatric comorbidity in the dominantly inherited movement disorder myoclonus-dystonia.

BACKGROUND: Neurological and psychiatric disorders show clinical overlap suggesting a shared pathophysiological background. We evaluated myoclonus-dystonia, a monogenic movement disorder as a disease model for inherited psychopathology. METHOD: We investigated 12 SGCE mutation carriers using standardized neurological and psychiatric examinations to assign DSM-IV diagnoses. Furthermore, we analyzed all studies in the Medline database which included psychiatric information on SGCE mutation-positive patients. RESULTS: Of our twelve SGCE mutation carriers, 10 were older than 16 years. Two of them (20%) reported psychiatric diagnoses before our examination, which resulted in at least one psychiatric diagnosis in seven (70%) patients, most frequently anxiety (60%), depression (30%) or both. Substance abuse was observed in 20%, whereas obsessive-compulsive disorders were absent. One mutation carrier showed Axis 2 features. In the literature analysis, the ten studies using standardized tools covering DSM-IV criteria reported prevalences similar to those in our sample. This was three times the frequency of psychiatric disorders detected in 13 studies using clinical history or patient report only. CONCLUSION: About two thirds of SGCE mutation carriers develop psychiatric comorbidity and >80% are previously undiagnosed.