Insights from system dynamics applications in addiction research: A scoping review

BACKGROUND AND AIMS

Substance misuse and use disorders are dynamic and complex problems, situated within systems of interacting social, environmental, and neurobiological factors. System dynamics (SD) methods broaden, test, and improve understanding of complex systems and can help inform effective action. We sought to systematically review the use of SD tools in addiction-related research.

METHODS

Following PRISMA guidelines, we searched several databases from 1958 to 2019. We included studies focused on addiction-related screening and diagnosis, treatment, and return to use, as well as studies focused on earlier stages that may begin a path to addiction (e.g., experimentation, misuse onset).

RESULTS

We extracted information from 59 articles with a median publication year of 2014. In addition to using SD to understand the underlying complexity driving addiction-related trends, other commonly cited reasons for use of SD included assessing impacts of potential actions (n = 35), predicting future trends (n = 28), and supporting strategic planning processes (n = 22). Most studies included simulation models (n = 43); however, some presented insights from qualitative SD diagrams (n = 9) and concept models (n = 6). The majority of studies focused on stages leading to potential addiction: initiation/ experimentation (n = 42) and misuse onset (n = 38). One-third (n = 20) engaged persons with lived experience or other stakeholders during the modeling process.

CONCLUSIONS

Addiction-related SD research has increased over the last few decades with applications varying in several ways, from model purpose and types of data used to stakeholder involvement. Future applications should consider the benefits of stakeholder engagement throughout the modeling process and expanding models to include concomitant substance use.

A Critical Perspective on Drug Selling in the United States: Can Transposition of the Dutch Model Succeed?

This is the first study of drug selling in the United States that attempts squarely and solely to place the problem of drug dealing within a “critical” criminological perspective. The drug issue is placed in historical and cross-national context; emphasized are a fundamental American ambivalence toward the issue of drugs and their control and the resultant cyclical quality of approaches to that control. “Left realism,” that branch of critical criminology deemed most theoretically and practically applicable to the drug issue, is explicated and compared with traditional perspectives within the sociology of crime. A “crime as work” thesis is developed; its essential tenets are explained, and remedial suggestions that flow logically from the thesis are highlighted. Emphasized is the unlikely prospect that the Dutch model, against which U.S. policy is compared, could profitably be transposed to resolution of the U.S. drug problem.

Key Data Gaps Regarding the Public Health Issues Associated with Opioid Analgesics

Most pharmaceutical opioids are used to treat pain, and they have been demonstrated to be effective medications for many. Their abuse and misuse pose significant public health concerns in the USA. Research has provided much insight into the prevalence, scope, and drivers of opioid abuse, but a holistic understanding is limited by a lack of available data regarding key aspects of this public health problem. Twelve data gaps were revealed during the creation of a systems-level computer model of medical use, diversion, nonmedical use, and the adverse outcomes associated with opioid analgesics in the USA. Data specific to these gaps would enhance the validity and real-world applications of systems-level models of this public health problem and would increase understanding of the complex system in which use and abuse occur. This paper provides an overview of these gaps, argues for the importance of closing them, and provides specific recommendations for future data collection efforts.

Modeling the impact of simulated educational interventions on the use and abuse of pharmaceutical opioids in the United States: a report on initial efforts

Three educational interventions were simulated in a system dynamics model of the medical use, trafficking, and nonmedical use of pharmaceutical opioids. The study relied on secondary data obtained in the literature for the period of 1995 to 2008 as well as expert panel recommendations regarding model parameters and structure. The behavior of the resulting systems-level model was tested for fit against reference behavior data. After the base model was tested, logic to represent three educational interventions was added and the impact of each intervention on simulated overdose deaths was evaluated over a 7-year evaluation period, 2008 to 2015. Principal findings were that a prescriber education intervention not only reduced total overdose deaths in the model but also reduced the total number of persons who receive opioid analgesic therapy, medical user education not only reduced overdose deaths among medical users but also resulted in increased deaths from nonmedical use, and a "popularity" intervention sharply reduced overdose deaths among nonmedical users while having no effect on medical use. System dynamics modeling shows promise for evaluating potential interventions to ameliorate the adverse outcomes associated with the complex system surrounding the use of opioid analgesics to treat pain.

System dynamics modeling as a potentially useful tool in analyzing mitigation strategies to reduce overdose deaths associated with pharmaceutical opioid treatment of chronic pain

OBJECTIVE

To illustrate a system-level, simulation-based approach for evaluating mitigation strategies to address the dramatic rise in abuse, addiction, and overdose deaths associated with the use of pharmaceutical opioid analgesics to treat chronic pain. SIMULATED INTERVENTIONS: Making available drug formulations with increased tamper-resistance, prescriber education programs, and programs that reduce rates of medical user-related abuse and addiction. SIMULATED OUTCOME MEASURE: Number of overdose deaths of medical users of pharmaceutical opioid analgesics, including those who abuse or have become addicted.

METHODS

A demonstration system dynamics model is developed, tested, and used to evaluate the impact of candidate mitigation strategies on the outcome measures.

RESULTS

Tamper-resistant drug products will likely reduce overdose death rates but may not reduce overall deaths if there is increased prescribing. Prescriber education would likely reduce deaths through a reduction in patient access to pharmaceutical opioid analgesics.

CONCLUSIONS

The system dynamics approach may have potential for opioid-related policy evaluation. However, metrics must be carefully selected, and trade-offs may be involved. For example, it may be difficult to limit negative outcomes associated with pharmaceutical opioids without adversely affecting chronic pain patients' access to pharmaceutical treatment. Ultimately, a combination of metrics and value judgments will be needed to properly evaluate mitigation strategies.

Dynamic compartmental model of trends in Australian drug use

A five-state compartment model of trends in illicit drug use in Australia is parameterized using data from multiple sources. The model reproduces historical prevalence and supports what-if analyses under the assumption that past trajectories of drug escalation and desistance persist. For fixed initiation, the system has a unique stable equilibrium. The chief qualitative finding is that even though some users escalate rapidly, regular injection drug use still adjusts to changes in incidence with considerable inertia and delay. This has important policy implications, e.g., concerning the timing of reductions in drug-related social cost generated by interventions that reduce the social cost per injection user versus those that cut drug initiation.