Five-factor personality is associated with aggression and mental distress in violent offenders

Background Five-Factor Model (FFM) personality traits, in particular low Agreeableness, low Conscientiousness, and high Neuroticism, have previously been associated with increased aggression and antisocial behavior [1]. Interestingly, the same personality characteristics have also been consistently linked to mental distress [2] and increased risk of psychopathology [3]. This is of relevance as both individual personality differences and mental distress, i.e., subclinical symptoms of stress and depression, have been found to influence important factors in the treatment of violent offenders, e.g., treatment motivation [4] and overall attrition rates [5]. Assuming the same FFM personality traits underlie both aggression and mental distress, insight into this relation could therefore have implications for assessment of treatment readiness as well as inform targeted interventions in criminal aggression. Yet to date, no studies have investigated whether FFM personality traits related to aggression are also associated with higher levels of mental distress within a cohort of violent offenders. Methods Forty male offenders (age, 19–59) with a documented history of violent and impulsive crimes (e.g., murder, attempted murder, rape, aggravated assault, robbery) were recruited from two closed state prisons in Denmark along with forty matched healthy non-offender controls (age, 18-54). All study participants completed the NEO Personality Inventory-Revised (NEO PI-R), the Buss-Perry Aggression Questionnaire (BPAQ), and self-report measures assessing mental distress. Group comparisons for each of the five NEO personality traits were carried out using ANCOVA. Within the violent offender group, linear regression models were used to investigate associations between NEO personality traits and trait aggression and mental distress respectively. All models were corrected for age, education, and IQ. Results Compared to non-offender healthy controls, the violent offenders scored significantly lower on Agreeableness ( F (77) = 10.3, p = 0.002), including the subfacets Trust, Altruism, and Compliance. Within the violent offender group, Agreeableness was negatively associated with trait aggression ( β = -0.67, p R 2 = 0.36) while Neuroticism, including the subfacets Angry Hostility and Impulsivity, was positively associated with both trait aggression ( β = 0.37, p = 0.01, R 2 = 0.27) and mental distress ( β = 0.28, p R 2 = 0.46). Conclusion Our findings support previous reports that FFM personality traits are associated with aggression as well as mental distress. Specifically, our findings indicate that high Neuroticism is associated with both increased aggression and mental distress in violent offenders. Further, low Agreeableness differentiates non-offender controls from violent offenders and is associated with increased aggression in the latter group. We argue that the inclusion of FFM personality assessment in correctional settings may be used as a stratification tool for targeted rehabilitative treatment in violent offenders.