ABSTRACT
OBJECTIVE: To investigate the specificity of the 'jump-to-conclusions' (JTC) bias in delusions. METHODS: Thirty-seven psychotic patients were divided into two separate groupings: (1) deluded versus non-deluded individuals and (2) individuals with and without a diagnosis of schizophrenia. Groups were compared on three reasoning tasks ('Beads' task, Wason's 2-4-6 task, and Wason's selection task). RESULTS: Deluded participants had a tendency to show a JTC bias on data-gathering tasks, but no differences were found with the schizophrenia diagnosis grouping. There were no differences between any groups on tasks of general reasoning and probability judgments. CONCLUSION: The results suggest that JTC is specific to delusions rather than diagnosis, and to data gathering rather than a general deficit in reasoning.
Subject(s)
Cognition Disorders/diagnosis , Delusions/diagnosis , Psychotic Disorders/diagnosis , Schizophrenia/diagnosis , Adolescent , Adult , Aged , Cognition Disorders/psychology , Decision Making , Delusions/psychology , Diagnostic and Statistical Manual of Mental Disorders , Female , Humans , Intelligence , Judgment , Male , Middle Aged , Psychiatric Status Rating Scales/statistics & numerical data , Psychometrics , Psychotic Disorders/psychology , Schizophrenic Psychology , Sensitivity and Specificity , Task Performance and AnalysisABSTRACT
BACKGROUND: This study reports short scales for measuring several dimensions of schizotypy in the normal population based on a large twin sample. METHODS: The four short scales use items drawn from a longer instrument, the Oxford-Liverpool Inventory of Feelings and Experiences. Using concordance estimates from MZ and DZ pairs, the items were selected both to have a high heritability and to offer broad coverage of each trait domain. RESULTS: Preliminary descriptive statistics are reported for the short scales and suggest adequate reliability. CONCLUSIONS: New scales offer a time efficient and reliable method of studying proneness to psychosis in large N designs.
