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A new 18-item checklist provides the first reliable clinical tool for assessing paranoid thinking in young people. Research found the Bird Checklist of Adolescent Paranoia (B-CAP) gave precise estimates of the severity of paranoia. It was most reliable for moderate to severe levels.

Paranoia is a neglected problem in young people. Before this research, there was no widely-accepted way of detecting paranoid thoughts in adolescents.

The researchers say the B-CAP could help identify paranoia in young people and monitor their response to treatment. It could be routinely used by mental health services such as child and adolescent mental health services (CAMHS) and early intervention in psychosis services (EIS). Further evaluation of the B-CAP in clinical practice and in adolescents from different social and ethnic backgrounds will be helpful.

The B-CAP also has promise as a so-called adaptive test that adjusts itself to the severity of paranoia. The research found that an adaptive B-CAP reliably estimated severe paranoia with fewer questions. This could make the checklist easier for young people to complete.

What’s the issue?

Paranoia is the unfounded idea that others want to harm you. It is relatively common in adolescents, with up to one in three (20% to 30%) experiencing suspicious thoughts at least weekly. At extreme levels, paranoia may be a symptom of a psychotic disorder, but it also likely to occur alongside many mental health problems in youth.

Thinking that others are out to get you can leave young people feeling scared when going outside and mistrustful in relationships. This social impact could worsen outcomes for young people with paranoia.

To ensure young people get help and treatment quickly, clinicians need to accurately detect paranoid thinking. But to date, there has been a lack of valid, reliable, and age-appropriate measures of paranoia for adolescents, especially among those with mental health problems.

The researchers therefore developed the B-CAP as a new test for paranoia in adolescents. In this study, they wanted to see if the checklist was reliable at different levels of paranoia and in different populations. They also wanted to see if the B-CAP could be used as a computer-based adaptive test. The number of questions on an adaptive test can change and may be reduced in response to early answers. This makes the assessment itself easier for young people to go through.

What’s new?

This study analysed B-CAP data from 801 pupils (11–15 years) from a secondary school in Leicestershire and 301 patients (11-17 years) attending CAMHS in Oxfordshire.

The researchers used a technique called item response theory (IRT) to evaluate the B-CAP. IRT takes into account the differences in how each question measures paranoia. It gives a more precise score compared with traditional methods.

Young people in the study were asked to respond to questions such as ‘people are making sly comments to upset me’ on a scale of 0 to 5, with 0 meaning they never thought it and 5 meaning they thought it all the time.

The results showed that:

  • all questions detected small differences in the severity of paranoia
  • none of the questions were biased by demographic factors such as age or gender
  • a score of 4 or 5 on any question indicated severe paranoia
  • certain questions such as ‘I feel like I am being followed or stalked’ and ‘people will try to kidnap me’ were linked to severe paranoia even if scored only as 1 or 2
  • the checklist was most reliable for moderate paranoia and remained high at extreme levels
  • a score of 34+ was an indicator of mildly elevated paranoia, 40+ of moderate paranoia, 56+ of high paranoia, and 71+ of severe paranoia
  • a computerised model - based on the responses from all 1,102 adolescents - showed that the B-CAP performed well as an adaptive test and 5-6 items was usually sufficient to accurately estimate severe paranoia.

Why is this important?

Paranoia tends to emerge in adolescence but may be a neglected problem, the researchers say. Little is known about the key signs, it is not routinely measured in youth services, nor is its assessment included in any NICE guidance for young people.

The B-CAP provides a reliable measure to detect paranoia across the spectrum of severity. It detected paranoia at the average levels expected in most adolescents, and at more severe levels in those with mental health problems. This means it could be used in a range of services.

In child and adolescent mental health services (CAMHS), the B-CAP could be used to screen young people for paranoia. It could also be used to monitor change over time and their response to interventions. This would allow more young people to access support to overcome paranoia and to feel safer around others.

What’s next?

The B-CAP is already being used by the researchers and their colleagues in local services. They say the checklist is ready to use by clinicians and researchers wanting to assess paranoia in teenagers. However, further evaluation of the B-CAP in clinical services and in adolescents from different social and ethnic backgrounds is needed to determine its true potential.

This study is part of larger programme of research that aims to improve the assessment and clinical understanding of paranoia in adolescence. This next step is to develop and test interventions to help young people with paranoia develop trust in others and feel safer in their daily lives.

You may be interested to read

The full study: Bird JC, and others. The assessment of paranoia in young people: Item and test properties of the Bird Checklist of Adolescent Paranoia. Schiz Res. 2020;220:116-122

Assessment tools, including the B-CAP, are available to download on the Oxford Cognitive Approaches to Psychosis (O-CAP) research group website

Related work on paranoia in adolescents by the same group: Bird JC, and others. Paranoia in patients attending child and adolescent mental health services. Australian and New Zealand Journal of Psychiatry. 2021. doi: 10.1177/0004867420981416

Also from the same group: Bird JC, and others. Adolescent Paranoia: Prevalence, Structure, and Causal Mechanisms. Schiz Bulletin. 2019;45:1134-1142


Funding: This research was funded by an NIHR research professorship awarded to Daniel Freeman with additional support by the NIHR Oxford Health Biomedical Research Centre.

Conflicts of Interest: The study authors declare no conflicts of interest.

Disclaimer: NIHR Alerts are not a substitute for professional medical advice. They provide information about research which is funded or supported by the NIHR. Please note that views expressed in NIHR Alerts are those of the author(s) and reviewer(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.

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Study author

This study shows that the B-CAP is a robust and clinically useful tool for assessing paranoia in adolescents. Not only is it short and easy to administer, but it can accurately measure the full spectrum of paranoia from average to severe. Its use in services could help start conversations about paranoia with young people and make sure it isn’t missed. This is important as mistrust of others – a core part of paranoia – could stop adolescents from voluntarily bringing up their suspicions with clinicians and parents. The real value of the B-CAP, however, will only be known with ongoing use and evaluation.

Jessica Bird, Clinical Psychologist & NIHR Research Fellow, Department of Psychiatry, University of Oxford

Child and Adolescent Psychiatrist

Health professionals working in child and young people’s mental health services (CYPMHS) and teams working in early intervention in psychosis (EIP) will be interested in this study. It shows that the use of the B-CAP checklist could be helpful in the assessment of young people presenting with paranoid ideas. It also highlights the need for clinicians to think about the root causes of different symptoms in psychosis.

The study could influence guidelines for early intervention in psychosis. Further research will be needed before the B-CAP could be used in clinical work, and before it could form part of NICE guidance for psychosis. This study provides reasonably robust evidence to support the use of B-CAP in young white British people but further study will be needed in other populations for the test to be used more widely.

Clare Fenton, Consultant Child and Adolescent Psychiatrist, Hull and York Medical School

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