Complex system structures around drug-related deaths in Scotland: a mixed method network analysis approach to study subsystems in population data and system maps

Background Drug-related deaths are rising in many countries. Understanding connections between health conditions, social experiences, and broader political factors may enhance death prevention efforts. Systems science methods can help identify areas for effective interventions. This study aimed to understand the complex system relating to drug-related deaths in Scotland. Methods We used gaussian graphical models to identify co-occurring variables in linked datasets: Public Health Scotland’s National Drug-Related Deaths Database, Prescribing Information System, and Scottish Morbidity Records for inpatient and day case stays in acute and psychiatric hospitals (n = 6,608). Preliminary findings were integrated into co-production workshops. We conducted a systems-informed intervention development study using the 6SQuID Intervention Development framework. We facilitated co-production workshops using soft systems methods and system mapping. System map factors were coded according to the social ecological model of health. Network metrics and Louvain community detection were applied to the system map and linked data graphical model. We applied a mixed method visual, text, and numeric approach to integrate findings from both data sources. Results Stigma, mental health and poverty were central factors in the system map; while population data found living arrangements and assault as central. Linked data analysis found 78 subsystems; 58 related to distinct conditions, eight to co-occurring conditions, and 12 to substance use. System map analysis found eight subsystems including direct causes of death, life experiences, stigmatising attitudes, treatment services and public perspectives. All subsystems contained factors across multiple social ecological levels, but no single system traversed all levels. Assault and alcohol treatment and harms were distinct subsystems in the linked data but less prominent in the system map; while frailty and housing were common features of both data sources. Conclusions Integrating systems science and social ecological perspectives with network analysis provides novel insights into complex health issues, with practical implications for designing interventions. Future policy and practice should consider how to align actions more closely to system-level outcomes alongside individual and clinical outcomes. Increased attention to social, community and living environments would give Scottish drug death policy more comprehensive coverage of the drug death system.