Specific biomarkers of internalizing and externalizing characteristics among first-time driving while impaired offenders

Background Studies have described the externalizing (e.g., antisocial propensity) and internalizing (e.g., anxiety, depression) characteristics of driving while impaired (DWI) recidivism. However, the respective contribution of those characteristics to recidivism risk and their underlying mechanisms are still unknown. Cortisol, a stress hormone, is a biomarker underlying various high-risk characteristics. Studies have found that first-time DWI (fDWI) offenders and recidivists have lower cortisol reactivity (CR) than non-DWI drivers. In other high-risk populations, internalizing characteristics has been positively correlated to cortisol basal levels (CBL). To disentangle the distinct recidivism trajectories in the fDWI offender population, this study explored whether cortisol measures were markers of externalizing and internalizing characteristics. Aims Hypotheses 1: CR is lower among fDWI offenders with higher versus lower externalizing propensity (driving violations, criminal arrests, antisocial tendency, sensation seeking, impulsivity); 2: CBL is higher among fDWI offenders with higher versus lower internalizing propensity (anxiety, depression). Methods Male fDWI offenders (n = 126) were recruited and submitted to the following protocols: Millon Clinical Multiaxial Inventory (antisocial tendency, anxiety, depression); Addiction Severity Index (major driving violations, criminal arrests); Sensation Seeking Scale; Barratt Impulsivity Scale and salivary cortisol measured after a psychosocial stress task and during a resting day. Cluster analyses and ANOVA were performed. Results fDWI offenders with higher externalizing propensity have a lower CR compared to offenders with lower propensity (F(1, 124) = 5.85, p = .017). Moreover, CBL is higher among offenders with higher versus lower internalizing propensity (F(1, 124) = 5.55, p = .020).