The family history of children with elective mutism: a research report.

The family history was studied in children with elective mutism. The samples comprised a series of N = 38 children with elective mutism and a control group of N = 31 children with a similar behavioural phenotype, i.e., the combination of an emotional disorder and a developmental disorder of articulation or expressive language. Interviews were performed with the respective mothers. There was a clear excess of the personality trait of taciturnity in first-, second-, and third-degree relatives. Although mutism was reported almost exclusively in the group of relatives of children that manifested elective mutism, the differences between the two samples were not significant probably due to low frequencies. Disorders of speech and language were quite common in the relatives of subjects in both samples. Psychiatric disorders were more frequently reported in the families with an electively mute child. The study lends some evidence for the assumption that genetic factors may play a role in the etiology of elective mutism.