Phenothiazine Therapy and Perceptual Changes in Schizophrenia Patients

The commencement of phenothiazine therapy in acute non-paranoid schizophrenic patients was associated with turbulent perceptual changes. This finding was discussed in terms of increased sensitivity or vulnerability to sensory stimulation. Introduction Two methodologies, one perceptual (kinesthetic and visual figural aftereffects) and the other an EEG measure called the average evoked response, have revealed two characteristic styles: augmenting and reducing (see Barnes, 1976 for a review). An augmenter increases what is perceived; a reducer decreases what is perceived. These two methods are regarded as a measure of stimulus intensity modulation involving all sense modalities. Using the kinesthetic figural aftereffect (KFA), the visual figural aftereffect (VFA) and average evoked response (AER), researchers have reported that acute nonparanoid schizophrenic patients are usually extreme reducers (Buchsbaum, 1975; Buchsbaum and Silverman, 1968; Kelm, 1962, 1968; Landau et al., 1975; Petrie, 1978; Schooler et al., 1976; Silverman, 1964; Wertheimer, 1954; Wertheimer and Jackson, 1957). Phenothiazine medication has been found to be associated with augmenting on both KFA and AER measures (Buchsbaum and Silverman, 1968; Inderbitzen et al., 1970; Petrie, 1978; Singer et al., 1969). The effect of phenothiazines on the VFA has not yet been investigated. The purpose of the present investigation is to study the effect of phenothiazine medication on the VFA and test Petrie's (1978) prediction that a drug which changes a reducer to an augmenter (or vice versa) can induce a stimulus-governed perceptual style. In terms of the VFA used in the present study, a stimulusgoverned style would be one in which a figure in the visual field (called the test or T figure) is phenomenally displaced a relatively great distance away from another figure (called the inspection or I figure) which the S had previously fixated. This is the usual figural aftereffect (see Koehler and Wallach, 1944) which Petrie (1978) has called augmenting because the phenomenal I T distance has increased. 1. Department of Psychology, University of Saskatchewan, Saskatoon, Canada.