common manifestations of schizophrenia that may be seen in other disorders as well. They include restricted affect, confusion or bewilderment, and the sudden onset of paranoid, persecutory, and other types of delusions. Although not specifically indicative of schizophrenia, second-rank symptoms nonetheless may be useful for differential diagnosis in certain situations. They are the complement of first-rank symptoms. [part of a diagnostic classification system for schizophrenia proposed in 1938 by German psychiatrist Kurt Schneider (1887–1967)]