Relevant data from social science studies, relying on self-reports of convicted felons and on the hard sciences, propose a general linkage such that drug use or abuse is implicated in at least one of every six felonies. A complication in establishing linkages, however, has been the rise in designer drugs, substances resistant even to sophisticated laboratory detection. Further, varying drug positive rates may reflect divergent patterns of criminal disposition in certain jurisdictions, as well as variant methods of inquiry. Self-reports may be the only viable way of determining whether drug use functioned biochemically as the driving factor or the facilitator in criminal behavior. Pathological intoxication legislation and bandwidth infidelity in drug testing further complicate forensic investigations. In future inquiries to establish precise links between drug use and felony crime, biochemistry and neuropsychopharmacology will take the lead. 20 references, 2 figures. (Author abstract modified)