Structural and functional changes in an Australian high-level drug trafficking network after exposure to supply changes

Background: Illicit drug markets and associated supply changes (including changes in availability and purity) have been studied for many years but with limited attention to how drug trafficking networks adapt to such changes and the consequences thereof: the aim of this study. Methods: A longitudinal social network analysis was applied to a high-level drug trafficking network which supplied methamphetamine and other drugs over 15 years in Melbourne, Australia (1993-2007). Data were extracted from judges' sentencing comments, a biography, and mainstream media. Five time periods were devised, and supply changes (distinguishing between law-enforcement-caused and non-law-enforcement-caused) were coded in each period. Then, the associated structural and functional changes in the network were analysed within and between periods. Results: Thirty-two supply changes were identified, of which 59% were law-enforcement-caused and 41% not. Temporally associated structural and functional changes included a shift from mostly international trafficking to mostly domestic manufacture (and vice versa), recruiting corrupted public officials, decentralisation, as well as changes in network density, roles, and size. Despite 32 supply changes, the network continued to sell large quantities of drugs for at least 15 years. Conclusion: This research highlighted the complex adaptive nature of the illicit drug trade and its resilience to market change. Supply changes were associated with a variety of structural and functional changes in the network, some of which resulted in negative consequences such as corruption or the increased domestic manufacture of methamphetamine.