From traits to trouble: Exploring the role of Drug Abuse between Clinical Personality and Criminal Behaviour

This study investigated the mediating role of drug use history in the relationship between clinical personality patterns and criminal behaviour among convicted inmates, a topic that remains underexplored. A total of 450 convicted inmates from Kwara State participated, with ages ranging from 19 to 52 years (M = 36.7 ± 0.7). The study employed an ex post facto design with purposive sampling. Standardised instruments employed included the Drug Abuse Screening Test, the Millon Clinical Multiaxial Inventory, and the Brief Criminal Attitude Scale. The results revealed that clinical personality traits significantly predicted the previous drug use and abuse of the individuals (a-path: b = 0.28, t = 9.79, p < .01). In turn, drug use history was a significant predictor of criminal behaviour (b-path: b = 0.06, t = 3.68, p < .001). Moreover, clinical personality traits exerted a direct effect on criminal tendencies, even when drug use was considered (c-path: b = 0.02, t = 5.12, p < .05). Mediation analysis indicated that drug use history partially mediated the link between clinical personality and criminal behaviour (c′-path: b = 0.45, t = 14.07, p < .01; bootstrap CI = 0.007 to 0.027). In conclusion, the study shows that drug abuse serves as a significant but partial mediator in the relationship between personality and crime. These findings underscore the importance of structured psychological interventions and integrated treatment approaches that target both clinical personality traits and substance use histories to reduce criminal behaviour and recidivism.