IQ Moderates the Relation between Psychopathy and Juvenile Offending

Although evidence indicates that both psychopathy and intelligence independently predict juvenile offending, relations among IQ, psychopathy, and offending are inconsistent. We investigated whether intelligence moderates the relation between psychopathy and both income and aggressive offending concurrently and over time among 1,354 juvenile offenders enrolled in Pathways to Desistance, a prospective study of serious juvenile offenders in Philadelphia, Pennsylvania, and Phoenix, Arizona. Participants were assessed on intelligence, psychopathy, and self-reported offending at their initial interview (age range: 14–18 years old), and at 36 and 84 months later. Results indicate that intelligence moderates the concurrent relation between both income and aggressive offending and total psychopathy, as well as scores on Factor 1 (interpersonal/affective) and Factor 2 (social deviance); the 36-month prospective relation between all aspects of psychopathy and income offending; and the 84-month prospective relation between Factor 2 psychopathy and aggressive offending. As expected, higher levels of psychopathy are associated with higher levels of offending, but the highest levels of offending are evinced among youth with relatively higher levels of psychopathy and relatively higher IQ.

psychopathy, intelligence, adolescence, juvenile offenders, offending

“The current study investigated whether IQ moderates the relation between total, Factor 1, and Factor 2 psychopathy scores and both income and aggressive offending among a large, diverse sample of adjudicated adolescents cross-sectionally and longitudinally” (p. 25).

A total of 1,354 serious juvenile offenders enrolled in the Pathways to Desistance prospective study in Philadelphia, PA and Phoenix, AZ participated in this study. Participants were between the ages of 14 and 17 at the time of their arrest for any felony, excluding less serious property crimes, or a similarly serious nonfelony offense, including misdemeanor sexual assault or misdemeanor weapons offenses. Each participant was administered a computer-assisted interview as well as a number of assessment measures, including the PCL:YV (Psychopathy Checklist: Youth Version) to assess psychopathy, the WASI (Wechsler Abbreviated Scale of Intelligence) to assess intelligence, and the Self-Report of Offending (SRO) to assess offending behavior. Data were analyzed to determine the relations between psychopathy and offending and to determine whether IQ acts as a moderating variable in the relation between psychopathy and juvenile offending behavior (broken into aggressive offending and income-generating offending). Data were analyzed in terms of concurrent relations at baseline as well as in terms of predictors at 36- and 84-month follow-ups.

Results indicate that IQ moderates the relation between psychopathy and both aggressive and income-generating offending such that the highest levels of both aggressive offending and income-generating offending at baseline were found among youth with higher levels of IQ and higher levels of psychopathy.

Specifically, “Although higher scores on all measures of psychopathy are associated with greater offending in both IQ groups [higher and lower], the relation between psychopathy and baseline aggressive offending was stronger among offenders who had relatively higher IQ scores. More specifically, the highest levels of baseline aggressive offending were found among youth with higher levels of IQ and higher levels of psychopathy” (p. 27).

In addition, “Although higher scores on all measures of psychopathy were associated with greater offending in both IQ groups, the relation between psychopathy and baseline income[-generating] offending was stronger among offenders who had relatively higher IQ scores. Ore specifically, the highest levels of baseline income offending were found among youth with higher levels of IQ and higher levels of psychopathy” (p. 27).

At 36-month follow-up, “among juvenile offenders assessed as high in psychopathy, high IQ was associated with the highest levels of 36-month follow-up income offending variety scores” (p. 27). IQ did not appear to moderate the relation between psychopathy and aggressive offending at 36-month follow-up.

At 84-month follow-up, “among juvenile offenders assessed as high in psychopathy, high IQ was associated with the highest levels of 84-month follow-up aggressive offending variety scores” (p. 29). IQ did not appear to moderate the relation between psychopathy and income offending at 84-month follow-up.

“The most important finding from this study is that intelligence and psychopathy interact in their contemporaneous influence on juvenile offending, with higher levels of psychopathy and intelligence conferring the greatest risk among adolescents adjudicated delinquent. There are significant policy implications of this finding. Psychopathy was found to have a significant main effect in predicting juvenile offending both cross-sectionally and longitudinally, and thus may be a valid component in the assessment of risk in juvenile offender populations. However, courts must be cautious not to overrely on assessments of psychopathy in decision-making about juvenile sentencing, and instead consider multiple variables. For example, when making decisions about sentencing or treatment options, intelligence should also be assessed in conjunction with measures of psychopathy in determining outcomes for adolescents. Because adolescents with higher psychopathy and IQ may be at particularly elevated risk for offending, specialized interventions could be tailored to this at-risk group (e.g., programs that place a greater emphasis on teaching problem-solving and perspective-taking skills). Adolescents in this at-risk group are also more likely to reduce their offending gradually over time; thus, it may be beneficial to retain them in supportive, therapeutic services until they reach adulthood to increase their likelihood of ceasing to offend following adolescence” (p. 31).

Additional aspects of this paper that are worth noting include the clear presentation of current hypotheses and rationale, the clear and well-defined data analytic plan, and the manner in which psychopathy was assessed.

The last paragraph of the introduction (p. 25) presents clear, well-delineated hypotheses that provide a nice example of how current hypotheses should be linked to the underlying rationale provided by results of earlier research.

In addition, the data analytic plan as set out on page 27 provides a nice example of a clear, well thought out a priori data analytic strategy that allows for testing of current hypotheses as well as additional probing post hoc to determine directionality and significance of interactions.

Finally, “another important strength of this study was its assessment of psychopathy. Psychopathy was assessed using the PCL:YV, which involved a diagnostic interview and review of information from collateral sources and institutional files, which increases confidence in the accuracy of the assessment of psychopathy. Additionally, the analyses examined multiple aspects of psychopathy, which enabled an examination of whether a single factor was driving the results. The use of both cross-sectional and prospective data derived from multiple time points also adds to the evidence that the PCL:YV predicts juvenile offending concurrently and prospectively” (p. 31).

As always, please join the discussion below if you have thoughts or comments to add!