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Title: The psychobiological correlates of schizotypy in a student sample
Author: Barkus, Emma.
Awarding Body: Manchester Metropolitan University
Current Institution: Manchester Metropolitan University
Date of Award: 2005
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Growing evidence suggests psychotic symptoms such as auditory hallucinations may be normally distributed and occur in non-clinical as well as clinical individuals. Schizotypy is a measure of proneness to psychotic-like experiences. The aim of the study was to identify individuals prone to psychotic-like experiences (High schizotypes) and determine whether they differ from other individuals on psychological, behavioural and cognitive measures. Additionally the biological correlates of hallucinatory-like experiences were also investigated in high schizotypes. Participants who scored highly, around the mean and low on positive schizotypy (as defined by the Unusual Experiences subscale from the O-LIFE and the LSHS) completed a number of psychological measures, the Neurological Evaluation Scale and a signal detection task. Participants who produced a large number of False Alarms in the signal detection task were asked to complete the task in a functional magnetic resonance imaging (tMRI) scanner. Using principal components analysis the O-LIFE items were explained by two components: Cognitive Perceptual; and, Emotional and Social Functioning. Multidimensional scaling revealed the LSHS could be explained using three dimensions: Mental Imagery, Hallucinatory Experiences and their Explanations; Auditory Imagery; and, Cognitive Misattributions. High schizotypes differed from at least one of the other groups in reporting lifetime psychological symptoms, dissociative experiences, suggestibility, metacognitive beliefs and general health. The High schizo types displayed more neurological soft signs than the rest of the sample. In the signal detection task the High group were less sensitive than the other participants, although this did not reach significance. Both the High and Low groups demonstrated a more liberal decision making style compared to the Mean group. However, only the High group produced more False Alarms. The High group had the slowest reaction time on the first repetition of the task but became faster across the three trials. fMRI results for the High group participants revealed that False Alarms activated similar brain regions to those associated with auditory hallucinations in patients with schizophrenia. The O-LIFE and LSHS were successfully used to identify participants who scored highly on schizotypy. Further research is needed to determine the nature of those who score low on measures of schizotypy. Replication of the imaging study using a larger sample of participants is required to confirm the exploratory findings reported here.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available