The meta-analytic results also suggested that some of the findings varied across instruments and, in a few instances, appear to be instrument dependent. For example, a number of studies have supported the hypothesis that a maladaptive variant of openness to experience includes the cognitive and perceptual aberrations of schizotypal PD (e.g. Ross, Lutz, & Bailey, 2002; Trull, Widiger, & Burr, 2001; Wiggins & Pincus, 1989). However, our meta-analysis of FFM PD research suggests this is not the predominant finding. Of the studies included within this meta-analysis, significant correlations of schizotypal PD with FFM openness were confined largely to the administration of the SIFFM (Trull & Widiger, 1997), particularly for the facets of openness to ideas and fantasy. This instrument specific finding is consistent with the fact that the SIFFM includes an explicit assessment of maladaptive variants of openness whenever a person endorses an openness item. Perhaps then, it provides a more sensitive assessment of these traits than is obtained by either the NEO PI-R or the FFMRF (Trull & Widiger, 2002).
