Aspects of cognitive functioning in schizotypy and schizophrenia: evidence for a continuum model

This research consisted of two studies, the fundamental aim of which was to delineate the pattern of relationships between measures of cognitive task performance and both symptom subtypes in schizophrenia and their corresponding schizotypal personality traits in healthy individuals. Study 1 compared these relationships in healthy individuals using the Schizotypal Personality Questionnaire (SPQ) and Study 2 assessed the relationships between symptomatology assessed using the Scale for the Assessment of Positive Symptoms and Scale for the Assessment of Negative Symptoms (SAPS/SANS) and cognitive task performance in a group of patients with schizophrenia. The contribution of fluid intelligence to task performance was also examined. In Study 1 high levels of negative schizotypy were associated with reduced verbal fluency, and high levels of disorganised schizotypy were associated with reduced negative priming in the healthy participants. In Study 2, closely corresponding relationships between symptom measures and these tasks were found in the patients with schizophrenia. The associations between the symptom and cognitive measures were independent of the effects of fluid IQ on performance.