In the more than 30 years since the establishment of the National Institute on Drug Abuse (NIDA), significant strides have been made in understanding the biologic basis of addiction. This progress—largely the product of NIDA-sponsored research—has advanced the concept of addiction as a complex disease process, and in doing so, has ushered in a new era in addiction prevention and treatment.
Using cutting-edge technologies, NIDA-supported scientists are elucidating the neural circuitry and chemistry mediating addiction and laying the groundwork for the development of pharmacologic and behavioral therapies that target distinct components of the addiction disease process. Through this work scientists are also gaining insight into the factors that determine biologic vulnerability to addiction.
NIDA-sponsored research is also detailing the effects of drug abuse on major organ systems of the body, thereby broadening our understanding of the health consequences associated with substance addiction. In an effort to improve the effectiveness and implementation of new addiction treatments, NIDA has launched pioneering research and dissemination initiatives aimed at evaluating treatments in real-world settings and developing products that facilitate the rapid and high-fidelity implementation of this research.
Addiction Is a Brain Disease
The response to substance abuse in America has cycled between periods of relative tolerance and intolerance. Lacking empiric evidence to the contrary, many have viewed drug addiction as either a consequence of psychological disease or a matter of personal choice. These conceptions of addiction gave rise to treatments that, while steeped in good intentions, typically lacked a scientific basis and often delivered uneven results.
The groundbreaking discovery in the 1970s of an endogenous opioid system in the brain provided scientists with specific cellular and molecular clues that addiction is primarily a biologic disease. In the ensuing years, advances in molecular biology, genetics, and neuroimaging technologies allowed scientists to begin piecing together the brain's reward pathways, and to elucidate how these pathways are activated and altered by the acute and chronic use of illicit drugs.
These NIDA-sponsored research efforts have revealed compelling evidence that addiction is a brain disease that arises through the complex interaction of genetic, behavioral, and environmental factors and, as such, is most effectively prevented and treated through research-based approaches.
Pharmacotherapies for Addiction
The discovery that addiction reflects the “hijacking” of reward and reinforcement pathways in the brain has provided researchers with potential targets for pharmacotherapies aimed at interrupting key stages in the development of addiction. Much of this effort has focused on the discovery of agents to curb craving—an important factor in relapse to drug taking. Also under development are medications to ease the withdrawal symptoms that accompany detoxification, “vaccines” for blocking drug-induced euphoria and relapse to addiction, and treatments to reverse the effects of drug overdose.
The Consequences of Addiction: It's Not All in Your Head
NIDA-sponsored research has also shown that drug abuse can have acute and long-term consequences for multiple organ systems. Not surprisingly, the nervous system is hardest hit by addiction. Chronic use of some drugs can produce significant cognitive impairments that may persist long after the cessation of drug taking. Additionally, drugs of abuse can affect regulatory centers in the brain resulting in potentially fatal disruption of autonomic functions such as respiration and body temperature. Drugs of abuse can also impact cardiovascular function. For example, NIDA-sponsored research has confirmed that stimulant abuse can promote rapid and irregular heartbeat, heart attacks, and stroke. These effects likely reflect both the overstimulation of cardiovascular regulatory centers in the brain as well as the direct action of the drug on the heart muscle itself.
The route of drug administration creates additional health threats. For example, the smoking of various substances (including marijuana, heroin, and crack cocaine) has been implicated in certain forms of pulmonary damage including airway constriction and obstruction, emphysema, and possibly cancer. Similarly, the sharing and reuse of needles used to inject drugs facilitates the spread of blood-borne diseases, including HIV/AIDS and hepatitis types B and C.