The "Diagnostic and Statistical Manual of Mental Disorders (DSM)", first published in 1952, first included elective mutism in its third edition, published in 1980. Selective mutism was described as "a continuous refusal to speak in almost all social situations" despite normal ability to speak. While "excessive shyness" and other anxiety-related traits were listed as associated features, predisposing factors included "maternal overprotection", mental retardation, and trauma. Elective mutism in the third edition revised (DSM III-R) is described similarly to the third edition except for specifying that the disorder is "not" related to social phobia.