Comparisons between self-reported and interview-verified psychotic-like experiences in adolescents.

AIM

The 15-item positive subscale of the Community Assessment of Psychic Experiences (CAPE-P15) has been widely used for measuring self-reported psychotic-like experiences (PLEs). However, its validity has not been well established. This study aimed to explore the consistency of self-reported PLEs (PLEs-S) and interview-verified PLEs (PLEs-I) based on the same items of the CAPE-P15.

METHODS

A total of 1255 college students completed the CAPE-P15 for measuring lifetime and current PLEs. Half of the students with high-risk scores and 5% of the rest were interviewed through telephone. Telephone interviews were based on the items of the CAPE-P15 using the symptom criteria for attenuated positive symptom syndrome.

RESULTS

When considering the presence of PLEs only, all κ values and correspondence rates (CRs) fell below the thresholds. However, there was adequate consistency for lifetime PLEs when associated distress was also considered in self-report (κ = .432, CR = 90.0%). Among three factors, only bizarre experiences (BEs) showed adequate diagnostic accuracy in detecting lifetime PLEs when combined with distress. Cut-off points of 1.30 (sensitivity of 89.2% and specificity of 92.3%) and 1.57 (sensitivity of 79.2% and specificity of 73.8%) for frequency scores were found to best identify genuine PLEs during lifetime and in the past month, respectively.

CONCLUSIONS

Although the validity of the CAPE-P15 for genuine PLEs is unsatisfactory, the scale showed much better diagnostic accuracy when combined with associated distress, especially for detecting lifetime PLEs. Self-report items on BEs may be more sensitive and specific when identifying PLEs in late adolescence.