C9orf72 and psychotic disorder: Finally, it is noteworthy that, within twentieth-century case series of ALS with FTD-like involvement, a familiarity with other neuropsychiatric disorders (e.g., psychosis, mood disorders, and epilepsy) was noted (Table 1) this possibly representing an ante litteram recognition of the genetic association between the ALS-FTD spectrum and unrelated brain disorders, which is nowadays believed to be underpinned by the phenotypic heterogeneity yielded from C9orf72 mutations [25].