Toxicological Patterns of Psychoactive Substance Use as Predictors of Violent Behavioral Outcomes in Medico-Legal Cases: A Retrospective Cohort Study

Abstract

Background: Psychoactive substance use is frequently encountered in medico-legal practice and may influence aggression through effects on judgment, behavioral inhibition, arousal, and impulse control. However, substance-specific toxicological predictors of violent behavior remain insufficiently characterized in local forensic populations.

Objective: To determine toxicological patterns of psychoactive substance exposure and identify independent predictors of violent behavioral outcomes among medico-legal cases.

Methods: This retrospective cohort study included 120 adult medico-legal cases evaluated at the Department of Forensic Medicine, King Edward Medical University, and Lahore Medical and Dental College, Lahore, Pakistan, between January 2025 and February 2026. Demographic, clinical, behavioral, and toxicological data were extracted from institutional records. The primary outcome was documented interpersonal violent behavior associated with the index medico-legal event. Associations were evaluated using univariable and multivariable binary logistic regression.

Results: Overall, 67 cases (55.8%) had violent outcomes and 92 (76.7%) had at least one psychoactive substance detected. Alcohol was identified in 45 (37.5%), cannabis in 34 (28.3%), stimulants in 24 (20.0%), opioids in 22 (18.3%), and benzodiazepines in 16 (13.3%) cases; 35 (29.2%) demonstrated polysubstance exposure. Violence occurred in 80.0% of polysubstance-positive, 79.2% of stimulant-positive, and 75.6% of alcohol-positive cases. Independent predictors were previous violent behavior (aOR 4.31, 95% CI 1.68–11.05), stimulant positivity (aOR 3.71, 95% CI 1.26–10.93), polysubstance exposure (aOR 3.39, 95% CI 1.30–8.87), alcohol positivity (aOR 2.88, 95% CI 1.23–6.74), and male sex (aOR 2.41, 95% CI 1.02–5.71).

Conclusion: Violent medico-legal outcomes were independently associated with stimulant exposure, alcohol positivity, polysubstance use, and previous violence. Integrating toxicological findings with behavioral history may improve early forensic risk stratification.