Additional data on whether vividness of visual mental imagery is linked to schizotypal traits in a non-clinical population.

Our research group was interested to read the study by Oertel et al. (2009) which found a greater vividness of visual mental imagery in patients with schizophrenia, first-degree relatives, and high-schizotypy controls when compared to low-schizotypy controls, indicating that vivid mental imagery may be an independent symptom and trait marker for the psychosis continuum. However, we note that the comparison between high and low schizotypy controls relied on a relatively small sample size (N=24 in each). We have recently completed a comparable study comparing two such groups using a larger sample size, a more in-depth psychometric assessment of schizotypy and a specific measure that evaluated the vividness of visual mental imagery. We compared a group of nonclinical high and low schizotypy participants on the measure of mental imagery vividness, as well as a larger group of high and low delusional ideation participants on the same measure. The relationship between mental imagery and delusional ideation is of particular interest in the light of Currie's hypothesis that delusions result from imaginings being misidentified as beliefs (Currie and Jureidini, 2001) and prior studies that found high levels of vividness-based memory monitoring errors in people diagnosed with schizophrenia (e.g. Brebion et al., 1997).