Statement for the Record
Mr. Chairman and Members of the Committee:
I am Dr. Timothy P. Condon, Associate Director of the National Institute on Drug Abuse (NIDA), one of the research institutes at the National Institutes of Health. I am pleased to have been invited here today with my colleagues to testify at this important hearing to tell you what science has taught us about heroin addiction.
The National Institute on Drug Abuse (NIDA) supports over 85% of the world's research on the health aspects of drug abuse and addiction. It does this through a comprehensive research portfolio that incorporates many diverse fields of scientific inquiry and addresses the most fundamental and essential questions about drug abuse, ranging from its causes and consequences to its prevention and treatment. The scientific knowledge that is generated through NIDA research is providing us with new insights into addiction, and importantly, how to both prevent and treat it.
Today, in the United States, approximately 600,000 people are addicted to heroin. Data from several sources suggest that the number of people using heroin for the first time continues to escalate with a large proportion of these new users being young, with 90% being under the age of 26. Part of what may be fueling the rising numbers seen here in the Southwest is the ready availability of inexpensive black tar heroin. Black tar heroin derives its name from its color and consistency which results from the crude processing methods used to illicitly manufacture heroin in Mexico. Regardless of its form, black tar heroin is addictive with street purities ranging from 20 to 80 percent.
Heroin addiction is often associated with increased criminal activity and human suffering. In addition to the medical consequences of collapsed veins, increased risk of bacterial infections in the heart and lungs, in the past 10 years, there has been a dramatic increase in the prevalence of human immunodeficiency virus (HIV), hepatitis C virus (HCV), and tuberculosis among intravenous heroin users. From 1991 to 1995 in major metropolitan areas, the annual number of heroin-related emergency room visits has increased from 36,000 to 76,000, and the annual number of heroin-related deaths has increased from 2,300 to 4,000. The associated morbidity and mortality further underscore the enormous human, economic, and societal costs of heroin addiction. This is a problem that is widespread and growing and impacting every community in America, both rural and urban.
The good news is that we know more about how opiates such as heroin and morphine work to produce their myriad of effects than almost any other drug. From this scientific base, researchers have been able to develop a number of effective weapons to combat heroin addiction.
Heroin is chemically derived from morphine and is approximately three times more potent than morphine. Because of its chemical structure heroin is able to very rapidly enter the brain where it is actually converted into morphine. In the brain, morphine attaches to the natural opioid receptors also known as, endogenous endorphin receptors, where it can initiate its multiple physiological effects, including pain reduction, depression of heart rate and the slowing of respiration. It is heroin's effects on respiration, in particular, that can be lethal in the case of heroin overdose. Heroin also acts on the brain's natural reward circuitry to produce a surge of pleasurable sensations.
Advances in molecular biology, are providing scientists with tools such as new animal models, to better understand how heroin produces its addictive effects at the cellular and molecular levels. For example, we have cloned the genes for 3 opiate receptor subtypes, the so-called, mu, delta and kappa opiate receptors. In the past two years, using state-of-the-art genetic engineering technology, we have been able to create new strains of "knockout" mice that lack each one of these receptor subtypes. A number of studies now point toward the mu opiate receptor as being critical in mediating opiates' addictive effects. This type of information can be invaluable in designing new, more effective treatment medications that can specifically target cellular sites relevant to addiction.
Prolonged opiate use has been found to cause pervasive changes in brain function. The manifestation of these brain changes can be seen in the development of tolerance and physical dependence. With physical dependence, the body adapts to the presence of the drug and withdrawal symptoms often occur if use is discontinued or abruptly reduced. The first symptoms may occur within a few hours after the last time the drug is taken. The major symptoms peak between 24 and 48 hours and subside after about a week. However, some people have shown persistent withdrawal signs for many months.
Physical dependence and withdrawal were once believed to be the key features of heroin addiction. We now know that this is not the case entirely, since craving and relapse can occur weeks and months after the withdrawal symptoms are gone.
Understanding the biology of addiction has led us to develop a number of effective tools to treat heroin addiction and to help manage the sometimes severe withdrawal syndrome that accompanies sudden cessation of drug use. Through NIDA-supported research, for example, LAAM (levo-alpha-acetyl-methadol), a new drug for the treatment of heroin addiction was developed and is now available as a supplement to methadone. Both drugs block the effects of heroin and eliminate withdrawal symptoms. Treatment with methadone requires daily dosing. LAAM blocks the effects of injected heroin for up to three days. Research has demonstrated that, when methadone or LAAM are given appropriately, they have the ability to block the euphoria caused by heroin, if the individual does in fact try to take heroin. Methadone has allowed many heroin addicts to lead a productive life.
As good as these treatments may be, there is no silver bullet for treating heroin addiction. Research has shown, however that integrating pharmacological approaches with behavioral therapies is the most successful approach to treating drug addiction. Behavioral therapies, such as contingency management and cognitive-behavioral interventions for example, have both been found to compliment anti-addiction medications, such as methadone, successfully.
In an effort to give treatment providers another effective tool to combat heroin addiction, NIDA is working with the Food and Drug Administration and the pharmaceutical industry to bring to market a new medication called buprenorphine. This medication has the potential for administration in less traditional environments, thus expanding treatment to populations who either do not have access to methadone programs or are unsuited to them, such as adolescents. Buprenorphine would not be a replacement for methadone or LAAM, but yet another treatment option for both physicians and patients.
Buprenorphine is just one of a number of new treatment approaches that NIDA will be testing in our soon to be launched National Drug Abuse Treatment Clinical Trials Network. This Network will serve as both the infrastructure for testing science-based treatments in diverse patient populations and treatment settings, and the mechanism for promoting the rapid translation of new treatment components into practice.
In addition to testing new medications, a number of behavioral therapies such as cognitive behavioral therapies, operant therapies, family therapies, brief motivational enhancement therapy, and new manualized approaches to individual and group drug counseling are ready to be evaluated in real life settings. It is important to note that all new pharmacological therapies will be tested in conjunction with a behavioral therapy.
This community based Network will enable us to design treatments to meet the specific needs of special populations, such as those in rural communities.
Ultimately, we know that our best treatment is prevention. We also know that we must provide the public with the necessary tools to play an active role in preventing drug use in their own local communities. This is likely one of the reasons that the first ever research based guide, NIDA's "Preventing Drug Use Among Children and Adolescents," has become one of our most popular publications since we debuted it almost two years ago. This user-friendly guide of principles summarizes our knowledge gleaned from over 20 years of prevention research. Over 200,000 copies have been circulated to communities throughout the country. The prevention booklet is just one example of how we are bringing research to local communities, both rural and urban, to reduce drug use.
NIDA is also teaming with other federal agencies, such as two components of the Department of Justice, the Bureau of Justice Assistance and the Office of Juvenile Justice and Delinquency Prevention to help communities combat drug addiction. In conjunction with the Department of Justice, we are working to implement science-based prevention programs into schools and evaluate their effectiveness. All of NIDA's prevention activities reflect our commitment to target prevention interventions to the specific needs of youth at risk for drug abuse, including members of different ethnic groups.
In short, we are interested in providing community's with the tools necessary to reduce the Nation's overall drug use. Thus, in addition to our research to prevent and treat drug abuse, NIDA is also concerned about education on these topics.
NIDA has an active information dissemination program that develops and disseminates science-based materials on a continuous basis. Publications such as our Research Report Series and our INFOFAX, which is available on the world wide web or by calling an 800 number, present the latest information on drugs of abuse in a concise manner that is understandable to members of the general public.
We also have a strong science education program to ensure that our Nation's youth have accurate science-based information to make healthy lifestyle choices. For example, we have developed award winning materials such as our "Mind Over Matter" series that was sent to every middle school in the Nation. "Mind Over Matter" is a series of drug education brochures for students in grades five through nine to spark their curiosity and to inform them with the most up-to-date scientific research findings on the effects of drug abuse.
In conclusion, I would like to reiterate that 25 years of research has provided us with effective prevention and treatment strategies that can be used to combat heroin addiction, as well as other drug problems. Research has shown that these strategies are effective in reducing not only drug use but also in reducing the spread of infections like HIV/AIDS and in decreasing criminal behavior.
It is important that there be a sound platform of scientific research to build upon as communities around the country develop and implement their drug abuse prevention and treatment programs. NIDA supported research continues to lead the way in strengthening and expanding that platform.
Thank you once again for inviting me to participate on this panel. I will be happy to answer any questions you may have regarding the scientific findings I just presented.