Relationships between dimensional factors of psychopathy and schizotypy

Katie A Ragsdale,Jeffrey S Bedwell

doi:10.3389/fpsyg.2013.00482

Abstract

Existing research has suggested that comorbid psychopathy may explain one trajectory of violent behavior in a subset of individuals with schizophrenia. However, it remains unclear which specific traits and symptoms are responsible for this relationship and whether it is limited to clinical and/or forensic categories, or if it reflects a dimensional relationship found in the general population. Therefore, the aim of this study was to examine differential relationships between specific factors of psychopathy and schizotypy in a non-psychiatric and non-forensic sample. Two hundred and twelve undergraduate students (50% female) completed the Schizotypal Personality Questionnaire (SPQ) and the Psychopathic Personality Inventory-Revised (PPI-R). After controlling for age and sex, regressions showed that the total SPQ score was positively related to the total PPI-R score and the Self-Centered Impulsivity factor, and negatively related to the Fearless Dominance factor. Self-Centered Impulsivity was positively related to all three SPQ factor scores, with the strongest relationship found with the Cognitive-Perceptual factor. In contrast, Fearless Dominance was negatively related to only the Interpersonal and Disorganized factors of the SPQ, with the strongest relationship found with the Interpersonal factor. Findings suggest that the comorbidity of schizotypy and the self-centered impulsivity aspect of psychopathy is not limited to extreme discrete populations, but exists in a more dimensional manner within a non-psychiatric sample. In addition, it appears that schizotypy is negatively related to the fearless dominance aspect of psychopathy, which appears to be a novel finding. Results provide preliminary findings that may have implications for developing appropriate prediction, assessment, and treatment techniques for violent behavior in schizophrenia-spectrum disorders.

Highlights

The majority of patients with schizophrenia are not violent, rates of violence are relatively higher for individuals with schizophrenia when compared to most other psychiatric disorders (Krakowski et al, 1986; Hodgins et al, 1996; Joyal et al, 2007), when schizophrenia is comorbid with substance abuse (Swanson et al, 1990; Erkiran et al, 2006)
In comparison to the general population, a meta-analysis found that 9.9% of individuals with schizophrenia or another psychotic disorder were violent compared to 1.6% of the general population; authors found no increased risk of violence in individuals with comorbid psychosis and substance abuse compared to individuals with substance use disorders only (Fazel et al, 2009)
Descriptive statistics are provided in Table 1, which shows that male participants had higher scores on the Psychopathic Personality Inventory-Revised (PPI-R) total and factor scores, as well as a statistical trend for higher scores on the Schizotypal Personality Questionnaire (SPQ) Interpersonal factor

Summary

Introduction

The majority of patients with schizophrenia are not violent, rates of violence are relatively higher for individuals with schizophrenia when compared to most other psychiatric disorders (Krakowski et al, 1986; Hodgins et al, 1996; Joyal et al, 2007), when schizophrenia is comorbid with substance abuse (Swanson et al, 1990; Erkiran et al, 2006). In one study, 8.36% of individuals with schizophrenia reported violent behavior compared to 3.45% of individuals with an affective disorder and 2.37% of individuals with an anxiety disorder (Swanson et al, 1990). A recent study found that individuals with schizophrenia were 4.57 times more likely than individuals without schizophrenia to have been found guilty of a violent offense (Short et al, 2013). Sex, and substance use were accounted for, individuals with schizophrenia were still 3.11 times more likely to have been found guilty of a violent offense, suggesting that increased violence in schizophrenia is not fully attributable to substance misuse

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