Do sex differences in emotionality mediate sex differences in traits of psychosis-proneness?

Abstract

The aim of the study was to determine if sex differences in emotionality might account for sex differences in distinct traits of proneness to psychosis (or "schizotypy"). Females report higher levels of "positive" schizotypy (e.g., magical thinking) than males, along with a tendency toward greater schizotypal disorganisation, whereas males report higher levels of "negative" schizotypal traits, such as social anxiety (Jackson & Claridge, 1991; Raine, 1992). Given the affect-oriented nature of "negative" schizotypal traits, we tested the hypothesis that higher levels of "negative" schizotypy among males would be accounted for by more general sex differences in emotionality; that is, by less frequent and less intense emotional experiences. A total of 81 student participants were administered the Cognitive-Perceptual Deficits, the Disorganisation, and the Interpersonal Deficits components of Raine's (1991) Schizotypal Personality Questionnaire (SPQ), indexing respectively, "positive" schizotypy, schizotypal disorganisation, and "negative" schizotypy. Frequency of emotional experience was assessed using the Emotionality subscale (Buss & Plomin, 1984) and intensity, the Affect Intensity Measure (Larsen & Diener, 1987). As predicted, males scored significantly higher than females on the SPQ Interpersonal Deficits component but no sex differences emerged for the other two components. Males reported significantly less intense, although not less frequent, experiences than females. A reduced intensity of positive emotions in particular was found to mediate the sex difference in "negative" schizotypy. Our results suggest that a less intense experience of positive affect might contribute to males' propensity to develop negative symptoms should a schizophrenic breakdown occur.