Investigating the multivariate relationship between impulsivity and psychopathy using canonical correlation analysis

- Over 70% of the variance in psychopathy and impulsivity scores was shared.
- Canonical correlation analysis showed a multidimensional relationship.
- Three statistically meaningful factors emerged, which were readily interpretable.
- Results support a multifaceted model of psychopathy.
- The Psychopathic Personality Inventory may be contaminated by impulsivity variance.

BackgroundImpulsivity is generally considered a core feature of psychopathy, however one problem with understanding the association between these constructs is that both are multifaceted. Existing research often treats one or both of these constructs as unidimensional with important information regarding the complex nature of the relationship being lost. To clarify this issue the present study employs a canonical correlation analysis (CCA) which allows for the comparison of two multifaceted measurement scales simultaneously.MethodsRespondents (n = 970) completed the Barratt Impulsiveness Scale (BIS-11) and the Psychopathic Personality Inventory (PPI). CCA was performed to explore the strength and nature of the association between impulse control and psychopathy.ResultsThere was a large correlation (r = 0.57) between BIS-11 and PPI total scores. Further exploration using CCA showed that 70.2% of the variance was shared between the subscales, and three significant canonical functions emerged. These were found to be interpretable and suggest that impulsivity relates to the broader psychopathy domain in a complex fashion, and that non-planning impulsivity may be the primary trait which distinguishes between psychopathy subtypes.DiscussionThe findings support a complex multi-dimensional relationship between impulsivity and psychopathy. The simple impulsivity-psychopathy correlation has much less explanatory power than has a multivariate approach.