Paranoia in adolescents: assessment, prevalence, and clinical understanding
Keywords: youth mental health
early intervention
paranoia
delusions
adolescents
network analysis

Background
Adolescence is the age when paranoia is most likely to first arise. Believing that others intend to harm you is likely to be corrosive for social relationships; this, in turn, could worsen outcomes for young people with mental health disorders. To date, however, paranoia has been predominantly studied in adults. Very little is known about its clinical presentation in adolescents. In this thesis, a systematic programme of research examining paranoia in adolescents - particularly those in clinical services - was conducted. The aims were to 1) develop an age-appropriate assessment of paranoia for young people, 2) establish the extent to which paranoia is a problem in adolescents attending mental health services, and 3) improve the clinical and theoretical understanding of paranoia at this age.
Method
After a systematic review of existing measures used to assess paranoia in the adolescent literature (Chapter 2), the development of a new measure of adolescent paranoia is described in Chapter 3. This measure was validated extensively using classical test theory and item response theory approaches in two cohorts: adolescents from the general population (n = 801) and patients accessing child and adolescent mental health services (CAMHS) (n = 301). A simulation of 10,000 responses was also conducted to evaluate the potential of the new measure as a computerised adaptive test. Next, this measure was used to examine the prevalence and potential correlates of paranoia in adolescents across the two cohorts of adolescents from a secondary school (Chapter 4) and patients accessing CAMHS (Chapter 5).
In the school cohort, an undirected network model and a Bayesian network with directed acyclic graphs (DAGs) was used to estimate probabilistic causal pathways between paranoia and theoretically important psychological factors and social factors relevant to adolescents (i.e. social media and peer interactions). In the CAMHS cohort, relationships between paranoia and both clinician-report and self-report psychiatric symptoms were examined using linear regressions and undirected network methods. The persistence of paranoia and its relationship with other difficulties several months later was assessed in a subgroup of the patients (n = 105). Finally, an interpretative phenomenological analysis (IPA) study using semi-structured interviews was conducted with 12 adolescent patients with paranoia in the context of non-psychotic mental health problems (Chapter 6).
Results
In Chapter 3, a new 18-item measure of paranoid thoughts for adolescents - the Bird Checklist of Adolescent Paranoia (B-CAP) - was created. The B-CAP was shown to be a valid and reliable measure with excellent psychometric properties for assessing paranoia in clinical and non-clinical populations of youth, with potential as an efficient adaptive test. In Chapter 4, paranoia in the adolescent general population was shown to follow a continuous distribution that closely fit an exponential curve. Occasional suspicions were common, and 15% of adolescents reported elevated levels. Paranoia was significantly higher in adolescent girls compared to boys, and was associated with clinical levels of anxiety, depression, and insomnia. DAGs analysis found paranoia closely interacted with affective processes and bullying, was more likely to impact peer relationships than vice versa, and had no causal relationship with problematic social media use.
The adolescent patients from the CAMHS cohort (Chapter 5) were primarily accessing services for emotional disorders. Only 2% had suspected psychosis. Rates of paranoia in these patients were approximately double those in the general population, with 35% reporting elevated levels. Yet paranoia was recorded in the clinical notes of only one participant. Paranoia was significantly higher in girls than boys and was associated with a range of clinician-rated problems including affective symptoms, self-harm, trauma, and impaired social functioning. Network analyses showed paranoia most strongly interacted with peer difficulties, and that paranoia had a central mediating role in the relationship between peer difficulties and most other symptoms. Follow-up data showed that paranoia remained persistent for three-quarters and was associated with greater psychological problems over time.
In the qualitative study (Chapter 6), young patients described a range of distressing paranoid concerns that were broadly overlooked by clinicians and untreated, despite regular contact with services. The young people’s accounts reflected a journey from the emergence of paranoia to the experience, and then, to adjusting to paranoia in daily life. Paranoia onset was rooted in the discovery of interpersonal threat and personal vulnerability, shaped by challenging peer interactions, becoming aware of danger in the world, and personal adverse experience. The paranoia experience included a struggle to trust friends, a state of threat anticipation, intense fear, and defensive strategies to keep safe. The patients described how the paranoia experience was confusing, negatively impacted self-concept, held them back from normal teenage life, and caused a disconnection from friends. Longer term responses to paranoia reflected a tension between reluctantly resigning to the experience and trying to resist the impact. Decisions about how adolescents respond to paranoia will determine the next stage of their journey.
Conclusions
There is a continuum of paranoia in the adolescent general population. Occasional suspicions are common at this age - more frequent paranoid thoughts, however, may indicate greater psychopathology. In patients attending CAMHS, paranoia is highly prevalent across a range of clinical presentations. It is likely to occur in the context of emotional problems, self-harm, adverse interpersonal experiences, and social impairment. Yet it may often be overlooked in services. Consistent with cognitive models of persecutory delusions, paranoia in adolescents is likely to build upon feelings of vulnerability and is closely linked to anxiety-processes concerned with anticipating danger. At this age, paranoia may involve navigating multiple tensions, with adolescents balancing independence with vulnerability, trust with mistrust, and the desire to socialise with a fear of danger and deception. Although the effects are potentially wide-reaching, there is a clear social impact of paranoia on adolescent peer relationships. Paranoia can be an understandable response to a changing and often-threatening social world in adolescence, but it is not inevitable nor without negative consequence. Greater awareness of paranoia in adolescents attending CAMHS is needed. Once identified, targeted interventions for paranoia, suitably adapted for this age group, would be the next step to help young people feel safer in their daily lives.