“…In contrast, all healthy controls responded and then habituated. While multiple studies have reported greater SCR frequency in the patients with schizophrenia than in healthy controls (Bernstein, 1967, 1970; Fenz and Velner, 1970; Gruzelier et al, 1981; Zahn, 1964; Zahn et al, 1968; Zahn et al, 1981), others have replicated the finding of a subgroup of patients who are SCR “non-responders.” According to recent reviews, approximately 40 to 50% of patients with schizophrenia are SCR non-responders (Bernstein et al, 1982; Dawson and Nuechterlein, 1984; Dawson et al, 2000; Öhman, 1981). Though SCR non-response is also observed in patients with other mental illness including depression, as well as in some healthy controls in some situations, the underlying physiology or pathology associated with the responder/ non-responder distinction seems to be different in schizophrenia, depression and healthy controls (Levinson, 1991; Öhman, 1981).…”