The Appropriate Use of Criteria for Schizophrenia

To the Editor.—  McGuffin et al¹ used what they purported to be our criteria for schizophrenia and found them to be unreliable and "unsatisfactory for detecting the familiality of schizophrenia." Our response is as follows.1. We substantially revised our criteria in 1978² by adding the requirements of first-rank symptoms and a clear consciousness to the inclusion criteria, and the presence of diagnosable affective disorder to the exclusion criteria, and by requiring the presence of only one (rather than all three) inclusion criterion for a diagnosis of schizophrenia. Nonetheless, McGuffin et al chose to use our 1975 criteria³; what was their rationale for doing so?2. Our 1975 criteria were not accurately portrayed by McGuffin et al. We nowhere referred to "incoherent speech," but specified "blocking, nonsequiturs, neologisms, word approximations, and verbigeration" as the types of formal thought disorder required. A "restricted affect" alone could not satisfy our