Behavioural and psychometric measures of impulsivity in a personality disordered population

Abstract

The relationship between psychometric and behavioural measures of impulsivity has not been extensively examined in violent personality disordered samples. We examined the relationship between psychometric and behavioural measures of impulsivity in 40 male, medication free, personality-disordered offenders with a history of violent offences. Subjects were categorized into high and low impulsivity groups based on psychometric measures and on the nature of their institutional violence. Group differences in performance on behavioural impulsivity measures were examined. High (trait)-impulsive subjects had significantly higher scores on all psychometric measures of impulsivity, poorer behavioural inhibition and an inability to delay gratification than low impulsive subjects. Within the institution, subjects who were categorized as predominately instrumentally violent had lower trait impulsivity, fewer incidents, and a greater ability to inhibit responses on behavioural tasks than those who were reactively violent. In the overall sample behavioural measures did not correlate well with psychometric measures of impulsivity and these measures appear to assess different constructs.

Keywords:

• impulsivity
• personality disordered offenders
• instrumental
• reactive
• aggression

ACKNOWLEDGEMENTS

We would like to thank Dr K Rubia for her help and advice, and for providing the Go/NoGo and Stop paradigms for use in this study and Isabelle Park for assistance in data collection.