1945, "person having schizophrenia," a slang shortening of schizophrenic. As an adjective by 1957. Alternative form schiz is by 1955 as a noun, 1960 as an adjective.
Entries linking to schizo
schizophrenic adj.
"characteristic of or having schizophrenia," 1912 (in translations of Bleuler); see schizophrenia + -ic. Also from 1912 as a noun, "schizophrenic person;" another attempted noun formation in English was schizophrene (by 1925), from German. Transferred adjectival sense of "contradictory, inconsistent" is by 1955. The jargon of psychology also produced schizophrenogenic "tending to spark or inspire schizophrenia."