The assessment of paranoia in young people: Item and test properties of the Bird Checklist of Adolescent Paranoia

Abstract

Background: Precise assessment tools for psychotic experiences in young people may help identify symptoms early and facilitate advances in treatment. In this study we provide an exemplar-with a paranoia scale for youth-for improving measurement precision for psychotic experiences using item response theory (IRT). We evaluate the psychometric properties of the new measure, test for measurement invariance, and assess its potential for computerised adaptive testing (CAT). Method: The 18-item Bird Checklist of Adolescent Paranoia (B-CAP) was completed by 1102 adolescents including 301 patients with mental health problems and 801 from the general population. After excluding outliers (n=10), IRT was used to examine item properties, test reliability, and measurement invariance. The properties of an adaptive B-CAP were assessed using a simulation of 10,000 responses. Results: All B-CAP items were highly discriminative (a=1.15-2.76), whereby small shifts in paranoia led to a higher probability of item endorsement. Test reliability was high (a>0.90) across a wide range of paranoia severity (θ=-0.46-3.36), with the greatest precision at elevated levels. All items were invariant for gender, age, and population groups. The simulated adaptive B-CAP performed with high accuracy and required only 5-6 items at higher levels of paranoia severity. Conclusions: The B-CAP is a reliable assessment tool with excellent psychometric properties to assess both non-clinical and clinical levels of paranoia in young people, with potential as an efficient adaptive test. In future, these approaches could be used to develop a multidimensional CAT to assess the full range of psychotic experiences in youth.

Paranoia in patients attending child and adolescent mental health services

“…Australian & New Zealand Journal of Psychiatry, 55( 12) (Bird et al, 2020). The B-CAP also demonstrates good concurrent validity with other measures of paranoia and adolescent's reports that their fears of others are excessive (Bird et al, 2019).…”

“…The Bird Checklist of Adolescent Paranoia. The Bird Checklist of Adolescent Paranoia (B-CAP; Bird et al, 2019Bird et al, , 2020) is an 18-item self-report scale for adolescents that assesses the frequency of paranoid thoughts in the past fortnight. Items are rated on a 6-point scale (0 = never, 5 = all the time) with higher scores indicating higher paranoia.…”

“…Three subtypes of paranoia are assessed within an overarching single construct: social harm, conspiracy ideas, and physical threat. The B-CAP has very good psychometric properties including strong reliability across the severity spectrum and measurement invariance for both age and gender in adolescents ( Bird et al, 2020 ). The B-CAP also demonstrates good concurrent validity with other measures of paranoia and adolescent’s reports that their fears of others are excessive ( Bird et al, 2019 ).…”

“…It is not possible in self-report questionnaires to determine if concerns about intended harm from others are unfounded. However, the B-CAP has shown good construct validity as a measure of unfounded ideation, with evidence that scores are distinct from bullying and are associated with adolescents' ratings that their fears of others are excessive (Bird et al, 2019(Bird et al, , 2020. Evidence also shows that, in general, self-report paranoia questionnaires predict genuine paranoid ideation in controlled virtual reality settings (Freeman et al, 2010(Freeman et al, , 2014.…”

Willingness of children and adolescents to have a COVID-19 vaccination: Results of a large whole schools survey in England

“…Measurement of depression and anxiety was from the 25‐item Revised Children's Anxiety and Depression Scales (RCADS) [21] . We measured paranoid thoughts using the 18-item Bird Checklist of Adolescent Paranoia (B-CAP) [22] .…”