A cluster analytic study of schizotypal trait dimensions

Several factor analytic studies reveal the existence of three distinct dimensions of schizotypy that appear to reflect the disposition to distinct schizophrenic syndromes (e.g. Bentall, Claridge & Slade, British Journal of Clinical Psychology, 28, 363–375, 1989; Claridge, McCreery, Mason, Bentall, Boyle, Slade & Popplewell, British Journal of Clinical Psychology, 35, 103–115, 1996; Muntaner, Garcia-Sevilla, Fernandez & Torrubia, Personality and Individual Differences, 9, 257–268, 1988). Claridge et al. referred to the dimensions as ‘Aberrant Perceptions and Beliefs’, ‘Cognitive Disorganisation’ and ‘Introvertive Anhedonia’. The present study sought to establish the ecological validity of the three dimensions by cluster analysing individual responses on the Oxford-Liverpool Inventory of Feelings and Experiences (OLIFE; Mason, Claridge & Jackson, Personality and Individual Differences, 18, 7–13, 1995). An agglomerative hierarchical cluster analysis of OLIFE subscale scores for 69 undergraduate psychology students revealed four separate clusters. Based on the defining feature(s) in each cluster, they were referred to as the Unusual Experiences, Cognitive Disorganisation, Introvertive Anhedonia, and Low Schizotypy subgroups. As indicated by these descriptive labels, three of the subgroups aligned broadly with previously denned dimensions of schizotypy, while the fourth subgroup reflected the overall absence of schizotypal traits. Thus, the results indicate that the three-dimensional structure of schizotypy suggested by Claridge et al. (1996) is reflected in naturally occurring subgroups of non-psychotic individuals.