Date of Award
PhD (Doctor of Philosophy)
Professor Mary Cannon
Psychotic Disorders, Diagnosis, Risk Factors, Adolescent
Epidemiological research has shown that hallucinations and delusions, the classic symptoms of psychosis, are far more prevalent in the population than actual psychotic disorder. These symptoms are especially prevalent in childhood and adolescence. Longitudinal research has demonstrated that psychotic symptoms in adolescence increase risk for psychotic disorder in adulthood. There has been little research, however, on the immediate clinicopathological significance of psychotic symptoms in adolescence and on the prevalence of prodromal risk syndromes in the community. Aims: Aim 1 : To assess the prevalence of psychotic symptoms and the association of psychotic symptoms with age and with DSM-IV Axis-1 psychopathology Aim 2: To assess the relationship between psychotic symptoms and suicidal behaviour Aim 3: To assess the neurocognitive profile of adolescents who report psychotic symptoms Aim 4: To assess the prevalence of prodromal risk syndromes in the population and assess associations with non-psychotic psychopathology and global functioning
Data from three population studies were used: Study 1 involved a school-based survey of 1,131 1 1 -to 13-year olds for psychotic symptoms, assessed using the Adolescent Psychotic Symptom Screener, and for emotional and behavioural symptoms of psychopathology, assessed using the Strengths and Difficulties Questionnaire. Studies 2 and 3 involved in-depth diagnostic interview assessments of psychotic symptoms and lifetime Axis-1 disorders in two community samples of 11-to 15-year olds, involving 423 adolescents in total. Psychotic symptoms, Axis-1 psychiatric disorders and suicidal behaviour were assessed using the Schedule for Affective Disorders and Schizophrenia (K-SADS). Global functioning was assessed using the Children’s Global Assessment Scale. Neurocognition was assessed using the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) consensus battery. Prodromal risk syndromes were assessed using the criteria of prodromal syndromes from the Structured Interview for Prodromal Syndromes.
A majority of community-based adolescents who reported psychotic symptoms had at least one lifetime diagnosable Axis-1 disorder on clinical interview: Study 2, Odds ratio (OR)=3.57, 95% confidence interval (CI95)=1.87-6.84, p
The majority of adolescents who report psychotic symptoms have at least one lifetime diagnosable Axis-1 disorder and demonstrate poorer neurocognitive performance than controls. Prodromal risk syndromes are relatively common in the community, which has implications for the proposed DSM-V diagnosis of Attenuated Psychosis Syndrome. Psychotic symptoms are important risk markers for severe multiple Axis-1 disorders and suicidal behaviour and should be routinely assessed in child and adolescent psychiatric clinics.
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Kelleher I. An Epidemiological Investigation of Adolescents and Symptomatic High Risk for Psychosis [PhD Thesis]. Dublin: Royal College of Surgeons in Ireland; 2012.