By Dr Wilson Compton, Director, Division of Epidemiology, Services & Prevention Research, US National Institute on Drug Abuse (NIDA)

The development of an effective, evidence-based public health approach to drug abuse must be built on three key pillars, argues Dr. Compton. The first is an understanding of how drug use affects, and is affected by, developmental brain-behaviour interactions. The second is a clear understanding of patterns in drug abuse. Finally, it is important to understand how policies can be implemented differently in different areas – with differing effects.

Drug abuse is a subject that is often overshadowed by irrational bias, stigma and discrimination. A public health perspective on drug abuse, however, needs to rely on an evidence-based approach if it is to maximise population benefit and minimise population morbidity.

Three key principles are essential to this process if a truly effective, evidence-based public health approach to drug abuse is to be realised:

• It must be understood that drug abuse and addiction are closely linked to developmental, brain-behaviour interactions;
• Public health efforts must begin by understanding changing trends in drug abuse;
• The policy environment interacts with and impacts individual behaviours and this pattern must be monitored to understand the real policy impact.

The link with developmental brain-behaviour interactions

Drug abuse and addiction involve multiple interactions between innate factors within the individual and various types of environments. These environments include intersecting and overlapping domains such as family, peer, neighbourhood, legal, and social levels. Each of these domains can influence an individual’s propensity to use drugs and to progress from drug use to addiction in concert with intra-individual factors such as genetic predisposition, innate response to substances and innate temperament (REF). Adding to the complexity, these intra-individual interactions with the environment may occur at specific developmental stages. The stage of development when exposure to the different environments occurs can be very important in determining outcomes (REF). For instance, a robust finding has been the observation that early exposure to a substance is highly correlated with later addiction (REF). The implication is that developmental factors are essential to understanding addiction.

At its most basic, addiction can be seen as a developmental disorder which is (at least partly) determined by an individual’s developmental trajectories. Interesting work has now documented that the pattern of an individual’s development of self-control in childhood predicts health, wealth, and public safety (Moffitt, 2011). Similarly, addiction can be viewed as a disease of the brain. This is illustrated in studies which document measurable differences in the brains of persons who are addicted to all substances compared to others (REF). It appears that the fine balance in connections that normally exists between brain areas active in reward, motivation, learning and memory, and inhibitory control becomes severely disrupted in addiction.

Understanding changing trends in drug abuse

A public health approach to drug abuse and addiction has to start by monitoring drug trends. Analysis of such epidemiological data provides clues about the causes of addiction and offers important guidance about where and how to focus treatment and prevention interventions.

For example, the Community Epidemiology Work Group (CEWG) at the U.S. National Institute on Drug Abuse identifies and interprets emerging drug trends in the United States. The experts in the CEWG interpret these trends through a local and regional lens based on the concept that drug abuse shifts at the local level. These local shifts are due to the interactions of social networks, including interpersonal and market forces which are now increasingly impacted by global forces facilitated via the Internet (REF). Without this level of local and regional understanding, an effective approach is much harder to achieve.

An area of major concern of late has included Prescription Drug Abuse, made particularly notable by an epidemic of unintentional drug overdose deaths in the USA in which recent increases in mortality have been correlated with increases in overall prescriptions for opioid analgesics (REF).

To address this epidemic, the public health perspective means that there is a need for new thinking about:

• Availability of drugs within homes and from friends and family;
• Unintentional misuse of medications as an intervention target in addition to their intentional abuse;
• The potential for direct overdose intervention by making naloxone more readily available;
• Relaxed attitudes and misperceptions about prescription drugs; &
• Drug disposal efforts to minimize environmental exposure to prescription-type agents (REF).

Monitoring the social & policy environment for important variations

A close monitoring of the social and policy environment is important in order to maximize population benefits. The tendency is to think of policies as uniform and with a single impact. In practice, policies are implemented within different regions in different ways. This variation allows assessment of the impact of policies by studying the different populations and may, of course, be based on the local situation which can demand variation in policies and their enforcement.

A model for tracking policies relevant to health in the substance abuse area is the Alcohol Policy Information System at the U.S. National Institute on Alcohol Abuse and Alcoholism (REF). The variation in alcohol-relevant policies (like other substance-related policies) across time at the state and local level allows thoughtful and useful evaluation of their impact (REF). An emerging area in the United States is the shifting approach to marijuana, with some 18 states having legalised marijuana for medicinal purposes (and most recently in 2 states for personal recreational use). How these shifts will impact overall rates of marijuana use and the health and social consequences related to marijuana is important and is the subject of multiple research projects (REF).

The goal of public health policy is to minimise the damage caused by substances and to maximize the public health benefit. I believe that a more pragmatic and detailed approach, adhering to the three principles described above, will be crucial in the implementation of robust evidence-based approaches that will reduce morbidity and mortality.