Alan I. Leshner, Ph.D.
Director, National Institute on Drug Abuse
National Institutes of Health
Department of Health and Human Services
June 7, 2001
- Many substances can be very effective medications when used properly, but highly addictive, dangerous, substances when misused. Morphine exemplifies this point. Morphine is a powerfully addictive drug. However, when it is used to treat pain it is an extremely effective medicine.
- When medications are used improperly they can pose a serious public health threat.
- Several indicators suggest that prescription drug misuse and abuse are increasing in the U.S. population.
- The National Household Survey on Drug Abuse reports that in 1999 more than 9 million Americans aged 12-and-older reported that they used prescription drugs at least once in the past year for non-medical reasons.
- One quarter or more of those 9 million people misused prescription drugs for the first time in the year prior to the survey.
- NIDA's Community Epidemiology Work Group, a network of epidemiologists and researchers from 21 major U.S. metropolitan areas who monitor and report on community-level trends in drug use and abuse, are also seeing increases in abused prescription drugs.
- Opiates, central nervous system depressants, and stimulants are three categories of psychoactive prescription drugs that are commonly abused.
- Because there are major differences among individuals in sensitivity to various drugs of abuse it is difficult to predict who will go on to abuse drugs and who will not.
- Research has not yet completely revealed all the reasons why people might abuse a prescribed medication. Some may just intentionally abuse these drugs to receive the pleasurable effects, in the same way that people abuse and become addicted to heroin or crack cocaine. Others may begin to use them appropriately, as prescribed, but then over time slowly begin to misuse them and then may find that they have become addicted.
- NIDA is encouraging more research on the topic of prescription drug abuse and misuse. NIDA has also launched an information campaign to better inform the public about this issue.
Testimony - Continuing Concern over Imported Pharmaceuticals
Mr. Chairman, and Members of the Subcommittee, I am pleased to be here to present what science has taught us about psychoactive prescription drugs and their potential for abuse. This discussion is particularly timely given that the National Institute on Drug Abuse (NIDA) has recently launched a major initiative on prescription drug abuse and misuse. NIDA's renewed efforts to encourage more research into this area and to educate the public about the consequences of abusing prescription drugs is a preemptive strike on our part to curtail what our surveillance systems suggest is a growing problem in this country.
At the outset, I would like to emphasize that many substances can be two things at once. They can be very effective medications when used properly; and highly addictive, dangerous, substances when misused. When used for legitimate medical purposes, controlled substances such as morphine and diazepam (Valium®), improve the quality of life for millions of Americans with debilitating diseases and conditions. It is only when these medications are used improperly that they begin to pose a serious public health threat. It is the increasing use of these medications for purposes other than how they were intended that is of growing concern to us.
Several indicators suggest that prescription drug misuse and abuse are increasing in the U.S. population. We know that in 1999 more than 9 million Americans aged 12-and-older reported that they used prescription drugs at least once in the past year for non-medical reasons. One quarter or more of those 9 million people misused prescription drugs for the first time in the year prior to the survey. And 4 million reported that they used prescribed medications for non-medical reasons in the past month. These data come from the National Household Survey on Drug Abuse, supported by the Substance Abuse Mental Health Services Administration.
NIDA's own Community Epidemiology Work Group, a network of epidemiologists and researchers from 21 major U.S. metropolitan areas who monitor and report on community-level trends in drug use and abuse, are also seeing increases in abused prescription drugs. The latest CEWG report, for example, reports that the opioid hydrocodone (e.g. Lorcet, Lortab, Vicodin) appears to be one of the mostly widely abused prescribed medications. The number of emergency room mentions of hydrocodone has grown by 139 percent, or from 6,115 mentions in 1993 to 14,639 in 1999. Other prescribed drugs that are emerging on the scene and are causing increases in emergency room visits, according to CEWG, are oxycodone and clonazepam.
Prescription drug abuse is not a new problem. The significant increase in the numbers of people misusing these prescription drugs is what is new. From 1990 to 1998, for example, the number of individuals initiating misuse or abuse of pain relievers increased by 181%, new initiates to stimulants have increased by 165%; tranquilizers by 132%; and initiates into sedative use have increased by 90%. The most dramatic increases are found in 12-17 year-olds and 18 to 25 year-olds. Females in this younger age bracket appear to be particularly vulnerable to prescription drug abuse.
Determining one's vulnerability to addiction is an important part of NIDA's research portfolio. The fact that we do not fully understand what makes some individuals more vulnerable to addiction than others makes our concern about prescription drugs even more compelling. There are major differences among individuals in sensitivity to various drugs of abuse. Using advanced technologies, we recently found that differences in brain chemistry may be one of the factors that predisposes people to respond differently to abusable drugs. Other determinants of drug use preferences and patterns include genetic and environmental factors, a possible underlying medical illness, as well as factors such as the availability of drugs.
What is significant about the brain chemistry finding that I just mentioned is that all abusable drugs -- from alcohol and nicotine, to cocaine, methamphetamine, and morphine – share some common mechanisms of action. They all activate the neurotransmitter dopamine, which is part of the reward pathway or pleasure center for the body. It is this pleasurable effect that is likely the reason that 26.2 million Americans used an abusable drug in the past year in 1999.
Although dopamine is a common factor among all drugs of abuse, each class of drug acts at different sites in the brain to produce its intended effect. For example opiates, such as morphine, codeine, and oxycocodone, work predominantly at the mu opioid receptors found in the brain and spinal cord, to block the transmission of pain messages to the brain.
Another commonly abused class of drugs is the Central Nervous System (CNS) depressants. CNS depressants modulate actions of gamma-aminobutyric acid (GABA) to slow down normal brain function. This resulting calming effect is what makes CNS depressants so useful in the treatment of anxiety and sleep disorders. Barbiturates such as mephobarbital and pentobarbital; and benzodiazepines such as diazepam and alprazolam, are two categories of CNS depressant medications that are commonly prescribed for anxiety and sleep disorders.
The final class of commonly abused prescription drugs that I will briefly mention today is stimulants. As the name suggests, stimulants are a class of drug that enhance brain activity. They cause an increase in alertness, attention, and energy by displacing two of the brain's key neurotransmitters, norepinephrine and dopamine, which in turn increases blood pressure, heart rate, respiration, and blood glucose. Stimulants such as dextroamphetamine, methylphenidate, and sibutramine are generally prescribed for narcolepsy, attention-deficit hyperactivity disorder, obesity, as well as depression, and asthma.
When taken properly all of these prescription drugs that I have just mentioned can be extremely helpful in relieving a wide variety of medical problems. It is when they are used non-medically, that prescription drugs can be dangerous, addicting and even deadly.
Research has not yet completely revealed all the reasons why people would abuse a prescribed medication. Some may just intentionally abuse these drugs to receive the pleasurable effects, in the same way that people abuse and become addicted to heroin or crack cocaine. Others seem to begin to use them appropriately as prescribed, but then over time they slowly begin to deviate from the prescription regimen and may become addicted without ever intentionally setting out to abuse the drug in the first place. It is important to note that physical dependence does not equal addiction. Physical dependence can be relatively easily managed, whereas addiction -- the compulsion to use drugs -- is a chronic reoccurring illness that requires long-term treatment.
As I mentioned earlier, the same substance can be both a very effective medicine and a dangerous addictive drug. Morphine, is the perfect example. Morphine is a powerfully addictive drug. However, when it is used to treat pain it is an extremely beneficial medicine. The medical use of prescribed opiates effectively relieves both chronic and acute pain, and allows millions of individuals to function normally. Addiction under these circumstances is very rare. In fact, the combined data from three clinical studies found that in patients with no prior history of abuse, opiates used for the treatment of pain was associated with only 7 cases of addiction in a sample of about 25,000 people.
Another example of how beneficial medications can be when used as prescribed can be seen with the stimulant methylphenidate, known commonly as Ritalin®. Data accumulated over 30 years shows that methylphenidate is a safe medication when appropriately used for the treatment of attention-deficit hyperactivity disorder (ADHD). ADHD affects about 3 to 5 percent of the general population and is now one of the most visible childhood mental disorders. A number of studies indicate that ADHD youth that are appropriately treated with stimulant medications have a reduction in the risk of later substance abuse.
In conclusion, I would like to thank you for allowing me to be here to have science be a part of your discussion on this topic. NIDA is increasing its research efforts into this area and will be pleased to keep you abreast of any new findings that emerge that may help guide your policy decisions.