Factor structure and age invariance of the Cardiff Anomalous Perceptions Scale (CAPS) in healthy older and younger adults

Although anomalous perceptual experiences are common in healthy older adults, they remain poorly characterized. In particular, it is unclear whether the phenomenology of these experiences differs between healthy older and younger adults. The current study examined similarities and differences in the factor structure of the Cardiff Anomalous Perceptions Scale (CAPS) in healthy, community-dwelling older (n = 194; Mage = 71.89, SD = 7.74, range = 52-91; 69.1% female) and younger adults (n = 421, Mage = 19.40, SD = 2.44, range = 17-34; 69.6% female; N = 615), using exploratory and confirmatory factor analysis, together with measurement invariance testing. The results found that a 2-factor correlated model comprising 23 of the original 32 CAPS items provided the best fit to the data. Further, scalar invariance was found between the two samples, indicating equivalence of the factor structure, factor loadings, and thresholds by age group. Compared with younger adults, the latent group means of older adults were also found to be equal on Factor 1, but significantly lower on Factor 2. Evidence of scalar age invariance on the CAPS suggests that this tool is valid for making comparisons between older and younger adults on two dimensions of anomalous perceptual experiences. Further, the results suggest that anomalous perceptions in the general community may be characterized by two components: anomalous body-centered self-experiences (e.g., alterations in body, touch, smell, and taste perception) and anomalous external experiences (e.g., auditory, visual, and sensed presence hallucinations); each of which may have different causes, correlates, and consequences for healthy ageing. (PsycInfo Database Record (c) 2020 APA, all rights reserved).