The purpose of the present study is to investigate dynamics underlying drug abuse and identify statistical correlations/patterns of forensic findings and sociodemographic factors in a population of illicit substance users. The following long‐term studies were conducted: (a) a retrospective autopsy cohort study on autopsy incidents with available toxicological screening results (N = 482) in investigation of any possible forensic associations of exposure to illicit drugs; and (b) a cross‐sectional study on a sample of arrested drug law offenders with available toxicological screening results (N = 195) as well as cluster analysis in order to possibly identify user profiles. Although outside the scope of the present study, ethanol was generally considered to be the main substance of abuse, as more than half of the premature deaths reported tested positive on the ethanol toxicology screen. Cannabis and opioid use was associated with unintentional causes of death, while an association of deliberate self‐harm was noted with opioid and benzodiazepine use. Both cannabis and opioid use correlated with significantly younger ages (more than a decade) of premature death. Most frequently, an onset of substance use was reported in the early 20s with cannabis use. Although 65.3% of the subjects were diagnosed as dependent and unable to eliminate substance use on their own, only 7.7% of the subjects in the users' population had ever accessed appropriate support through rehabilitation programs.