Characterization of psychotic experiences in adolescence using the specific psychotic experiences questionnaire: findings from a study of 5000 16-year-old twins.
We aimed to characterize multiple psychotic experiences, each assessed on a spectrum of severity (ie, quantitatively), in a general population sample of adolescents. Over five thousand 16-year-old twins and their parents completed the newly devised Specific Psychotic Experiences Questionnaire (SPEQ); a subsample repeated it approximately 9 months later. SPEQ was investigated in terms of factor structure, intersubscale correlations, frequency of endorsement and reported distress, reliability and validity, associations with traits of anxiety, depression and personality, and sex differences. Principal component analysis revealed a 6-component solution: paranoia, hallucinations, cognitive disorganization, grandiosity, anhedonia, and parent-rated negative symptoms. These components formed the basis of 6 subscales. Correlations between different experiences were low to moderate. All SPEQ subscales, except Grandiosity, correlated significantly with traits of anxiety, depression, and neuroticism. Scales showed good internal consistency, test-retest reliability, and convergent validity. Girls endorsed more paranoia, hallucinations, and cognitive disorganization; boys reported more grandiosity and anhedonia and had more parent-rated negative symptoms. As in adults at high risk for psychosis and with psychotic disorders, psychotic experiences in adolescents are characterized by multiple components. The study of psychotic experiences as distinct dimensional quantitative traits is likely to prove an important strategy for future research, and the SPEQ is a self- and parent-report questionnaire battery that embodies this approach.
Centre for Brain and Cognitive Development, Birkbeck, University of London, London, UK; a.ronald@bbk.ac.uk.
Angelica
A
Ronald
Centre for Brain and Cognitive Development, Birkbeck, University of London, London, UK;
Dominika
D
Sieradzka
Academic Unit of Psychiatry and Behavioural Sciences, University of Leeds, Leeds, UK;
Alastair G
AG
Cardno
Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, London, UK;
Claire M A
CM
Haworth
Institute of Psychiatry, King's College London, London, UK;
Philip
P
McGuire
Department of Psychiatry, University of Oxford, Oxford, UK.
Daniel
D
Freeman
D000293:Adolescent; D059445:Anhedonia; D001007:Anxiety / Q000453:epidemiology / Q000523:psychology; D003702:Delusions / Q000453:epidemiology* / Q000523:psychology; D003863:Depression / Q000453:epidemiology / Q000523:psychology; D005260:Female; D006212:Hallucinations / Q000453:epidemiology* / Q000523:psychology; D006801:Humans; D008297:Male; D010259:Paranoid Disorders / Q000453:epidemiology* / Q000523:psychology; D010551:Personality; D025341:Principal Component Analysis; D011618:Psychotic Disorders / Q000453:epidemiology* / Q000523:psychology; D012720:Severity of Illness Index; D017678:Sex Distribution; D006113:United Kingdom / Q000453:epidemiology
adolescence; anhedonia; grandiosity; hallucinations; paranoia; schizophrenia