Myotonia congenita (Thomsen's disease) and hereditary psychosis.
Thomsen believed there was a fundamental relationship between myotonia congenita and the hereditary psychosis which occurred in some members of his family.

A patient with myotonia congenita who had two acute psychotic episodes is described. Myotonia congenita was present in two other siblings. Acute psychosis of a "mixed" affective and schizophrenic type occurred in the father and four other male members of the family.

Myotonia congenita and the hereditary psychosis appeared to be transmitted independently in this family, and no direct relationship between the two disorders could be substantiated.