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.