This psychiatry weblog, authored by two Harvard University-trained psychiatrists and former lecturers at Harvard Medical School, offers you psychiatric news and commentary about brain disorders, mental dysfunction, psychological illness, and mental health wellness.
Drug
addiction is a brain disease. Although initial drug use might be
voluntary, drugs of abuse have been shown to alter gene expression and
brain circuitry, which in turn affect human behavior. Once addiction
develops, these brain changes interfere with an individual’s ability to
make voluntary decisions, leading to compulsive drug craving, seeking
and use.
The
impact of addiction can be far reaching. Cardiovascular disease,
stroke, cancer, HIV/AIDS, hepatitis, and lung disease can all be
affected by drug abuse. Some of these effects occur when drugs are used
at high doses or after prolonged use, however, some may occur after
just one use.
424432 since 2/8/07
Selected Research Findings on the Medical Burden of Drug Abuse
Burden of Medical Illness in Drug and Alcohol Dependent Persons without Primary Care Little
is known about the frequency, severity and risk factors for disease in
drug and alcohol dependent persons without primary medical care. This
article assesses the burden of medical illness and identifies patient
and substance dependence characteristics associated with worse physical
health in order to compare measures of illness burden in this
population. Researchers conducted a cross-sectional study among
alcohol, heroin or cocaine dependent persons without primary medical
care admitted to an urban inpatient detoxification unit (mean age =
35.7 years; 76% male; 46% Black). Forty-five percent reported being
diagnosed with a chronic illness, and 80% had prior medical
hospitalizations. The mean age-adjusted SF-36 Physical Component
Summary (PCS) score was significantly lower than the general U.S.
population norm (44.1 vs. 50.1). In multivariable analysis, the
following factors were associated with worse health: female gender,
problem use of hallucinogens, heroin, other opiates, living alone,
having medical insurance, and older age. Alcohol and drug dependent
persons without primary medical care have a substantial burden of
medical illness compared to age and gender matched U.S. population
controls. While the optimal measure of medical illness burden in this
population is unclear, a variety of health measures document this
medical illness burden in addicted persons. De Alba, I., Samet, J.H.
and Saitz, R. Burden of Medical Illness in Drug and Alcohol Dependent
Persons without Primary Ccare. American Journal of Addiction, 13, pp.
33-45, 2004.
Medical and Psychiatric Conditions Prevalent among Alcohol and Drug Treatment Patients in an HMO Prior
research on health conditions related to substance abuse largely
focused on alcohol and patients treated in publicly-funded programs,
inpatients, and the general population. This study compares the
prevalence of medical and psychiatric conditions among 747 substance
abuse patients and 3,690 demographically matched controls from the same
health maintenance organization, and examines whether any heightened
prevalence for substance abuse patients (relative to controls) varies
according to demographic subgroups and type of substance. Approximately
one third of the conditions examined were more common among substance
abuse patients than among matched controls, and many of these
conditions were among the most costly. Researchers also found that
pain-related diagnoses, including arthritis, headache, and lower back
pain, were more prevalent among such patients, particularly those
dependent on narcotic analgesics. These findings point to the
importance of examining comorbid medical conditions and substance abuse
in both primary and specialty care. Findings regarding pain-related
diagnoses among patients dependent on narcotic analgesics highlight the
need for linkages between primary care and substance abuse treatment.
Moreover, optimal treatment of many common medical disorders may
require identification, intervention, and treatment of an underlying
substance abuse disorder. Mertens, J.R, Lu, Yun W., Parthasarathy, S.,
Moore, C. and Weisner, C.M. Medical and Psychiatric Conditions of
Alcohol and Drug Treatment Patients in an HMO. Archives of Internal
Medicine, 163(20), pp. 2511-2517, 2003.
For related articles on Addiction
the Web, click on: “Sphere: Related Content” located at the bottom of this
blog post.
For related books or blog
posts with related content in Dr. Jeff’s and Dr. Tanya’s Blog, click on
the “Addictions: General” category at the bottom of the post or type in
keywords “Addiction” into “Google Search” located in the sidebar.
For related articles from
Psychology Today, click on the “Psychology Today” banner in the side bar
and type in Key words, “Addiction” into the Psychology Today “Search”.
For more books with related
content, click any hyperlinked key word in the blog or type in key words,
“Addiction“ into “Amazon Search” on the Amazon banner located in the side
bar.
Sources: National Institute of Drug Abuse; See also blogposts in: Addictions: Drug Abuse, and Psychiatry: Addictions: General
A number of our Nation's best monitoring mechanisms have detected an
alarming increase in the popularity of MDMA
(3,4-methylenedioxymethamphetamine), particularly among young
Americans. Unfortunately, myths abound about both the acute effects and
long-term consequences of this drug, also known as "Ecstasy," with many
young people believing that MDMA is safe, offering nothing but a
pleasant high for the $25 cost of a single tablet. But MDMA is not new
to the scientific community, with many laboratories beginning their
investigations of this drug in the mid 1980s, and the picture emerging
from their efforts paints a much different image of this drug, one that
is far from benign.
This report, Ecstasy: What We Know and Don't Know About MDMA,
represents a scientific review of what research has discovered about
how this drug works in the brain and what requires further study to
fully understand the consequences of using this illicit substance. This
report discusses what scientists know and don't know about MDMA's acute
effects on the brain and behavior from laboratory studies in both
animals and humans. The report also reviews the long-term effects on
the brain, again in both laboratory animals and humans, as well as
long-term behavioral consequences detected in chronic MDMA users.
MDMA, a relatively simple chemical belonging to the amphetamine family
of compounds, has properties of both stimulants and hallucinogens.
While MDMA does not cause true hallucinations, many people have
reported distorted time and perception while under the influence of
this drug. The vast majority of people take MDMA orally, and its
effects last approximately four to six hours. Many users will "bump"
the drug, taking a second dose when the effects of the initial dose
begin to fade. The typical dose is between one and two tablets, with
each containing approximately 60-120 milligrams of MDMA. However,
tablets of what users call Ecstasy often contain not only MDMA but a
number of other drugs, including methamphetamine, caffeine,
dextromethorphan, ephedrine, and cocaine.
One of the more alarming facts about MDMA is that despite its known
detrimental effects, there are increasing numbers of students and young
adults who continue to use the drug. Results from the 2000 Monitoring
the Future survey indicate that MDMA use increased among students in
the 12th, 10th, and 8th grades. African Americans show considerably
lower rates of MDMA use than do either whites or Hispanics. The recent
CEWG data showed a large increase in use among Hispanics that may
represent an important change.
Effects of Acute Doses of MDMA
MDMA works in the brain by increasing the activity levels of at
least three neurotransmitters: serotonin, dopamine, and
norepinepherine. Much like other amphetamines, MDMA causes these
neurotransmitters to be released from their storage sites in neurons,
increasing brain activity. Compared to the potent stimulant
methamphetamine, MDMA triggers a larger increase in serotonin and a
smaller increase in dopamine. Serotonin is a major neurotransmitter
involved in regulating mood, sleep, pain, emotion, and appetite, as
well as other behaviors. By releasing large amounts of serotonin, and
also interfering with its synthesis, MDMA leads to a significant
depletion of this important neurotransmitter. As a result, it takes the
human brain a significant amount of time to rebuild the store of
serotonin needed to perform important physiological and psychological
functions.
One hypothesis to explain the long-lasting neurotoxicity of MDMA on
serotonergic systems is that MDMA induces both oxidative and metabolic
stress in serotonin neurons that, in turn, adversely affect the ability
of these neurons to produce serotonin. Support for this hypothesis
comes from a variety of studies, including those showing that MDMA
perturbs the activity of various antioxidant enzymes; artificially
boosting the levels of these enzymes reduces MDMA's effects on
serotonin and dopamine neurons. Also, stress appears to increase the
oxidative damage caused by MDMA.
It has been difficult to study the effects of MDMA in humans under
controlled conditions, and virtually impossible until recently to
conduct simultaneous neurochemical studies. However, several groups of
researchers have chosen to study the behavioral pharmacology of MDMA in
various animal species, showing that MDMA and related compounds produce
a unique behavioral profile in rodents. Studies in non-human primates
suggests that acute doses of MDMA may have subtle effects on higher
cognitive functions, including memory and learning. Other experiments
in laboratory animals suggest that MDMA is a drug that humans are
likely to abuse, and that humans may develop tolerance to MDMA's
reinforcing effects. Limited studies in humans have shown that MDMA
negatively impacts short-term performance on a variety of measures of
cognitive ability.
Controlled studies in humans have shown that MDMA has potent effects on
the cardiovascular system and on the body's ability to regulate its
internal temperature. Of great concern is MDMA's adverse effect on the
pumping efficiency of the heart - in the presence of MDMA, increased
physical activity increases heart rate significantly, but the heart
does not respond in its normal manner, which is to increase the
efficiency with which it pumps blood. Since MDMA use is often
associated with sustained, strenuous activity, such as dancing, MDMA's
effects on the heart could increase the risk of heart damage or other
cardiovascular complications in susceptible individuals.
Pharmacokinectic studies have shown that MDMA is rapidly absorbed
into the human blood stream, but once in the body the metabolites of
MDMA inhibit MDMA metabolism. As a result, subsequent doses of the drug
produce unexpectedly high blood levels, which could worsen the
cardiovascular and other adverse effects of this drug without
increasing its "pleasurable" effects, which tend to peak about two
hours after taking an initial dose. MDMA interferes with the metabolism
of other drugs, including some of the adulterants in MDMA tablets.
Long-Term Consequences of MDMA: Neurochemical and Developmental
Acute doses of MDMA produce marked changes in both dopamine and
serotonin systems within the brain. Though the changes in dopaminergic
neurons appear transient, the data suggest that the changes in the
serotonergic system are longer-lasting. In addition, examinations of
more global brain function have shown that the effects of acute doses
of MDMA extend to regions of the brain that are thought to be involved
in higher thought processes. These findings have raised concern about
possible long-term effects on both infrequent and regular users of
MDMA.
Several groups have shown that exposure to MDMA rapidly and
persistently destroys a key marker of serotonergic function in regions
known to have a high density of serotonin neurons, including the
striatum and cortex. More detailed examination of this structural
damage shows that MDMA appears to prune, or reduce in number, serotonin
axons and axon terminals. Eighteen months after a short course of MDMA,
investigators found that some brain regions had substantial loss of
serotonin axon terminals, while a few others had more serotonin axon
terminals. This pattern is a hallmark of axon pruning, since nerve
cells will often grow replacement terminals upstream of the damaged
terminals. These results, then, are evidence not only of MDMA's
neurotoxicity, but of the brain attempting to rewire the serotonin
system after damage.
Since younger brains may have an increased susceptibility to the
neurotoxic effects of MDMA, it may be that the youngest, fastest
developing brains - those of a developing fetus - could be particularly
vulnerable to the effects of this apparent serotonin neurotoxin. Since
most MDMA users are young and in their reproductive years, it is
possible that some female users may take MDMA when they are pregnant,
either inadvertently or intentionally, because of the misperception
that it is a safe drug. Studies in animals have shown that MDMA has
little effect on the physical development of the young brain.
Behavioral and cognitive studies in laboratory animals, however, have
identified significant adverse cognitive effects from pre and neonatal
exposure to MDMA. This effect was not due to serotonergic
neurotoxicity; the mechanisms underlying the development of these
cognitive deficits are not known yet. Though the rodent experiments
have predictive value, it is not known whether human fetuses exposed to
MDMA when their mothers abuse the drug will develop persistent and
learning memory deficits.
Long-Term Functional Consequences of MDMA: Behavioral, Mood, Psychiatric, and Cognitive
Because MDMA produces long-term deficits in serotonin function, and
because serotonin function has been implicated in the etiology of many
psychiatric disorders including depression and anxiety, investigators
have suspected that MDMA users may experience more psychopathology than
non-users. Indeed, a number of investigators have found that heavy MDMA
users experience a constellation of psychiatric changes, scoring
significantly higher on measures of obsessive traits, anxiety, paranoid
thoughts, and disturbed sleep, among others. One study, aimed at
developing reliable measures of diagnosing substance abuse disorders,
found that 43 percent of MDMA users met DSM-IV criteria for dependence
and 34 percent met the criteria for abuse of MDMA.
There is a large and growing body of evidence from a variety of studies
with humans that MDMA use can have long-lasting effects on memory. None
of these studies are perfect, as they all have methodological concerns
such as concurrent use of other drugs (it is apparently impossible to
find but a few MDMA users who do not use other illicit substances,
particularly marijuana). In addition, results vary with the assessment
used. Nonetheless, the general finding that emerges across all of the
studies is that MDMA does impact memory abilities in ways that could
adversely affect normal functioning on every day tasks. Moreover, the
relationship between memory problems and MDMA use appears to have a
dose-dependent relationship, that is, the more MDMA used, the greater
the deficit.
Given that numerous studies have shown that the serotonin deficits
caused by MDMA are persistent, lasting at least seven years in one
study of nonhuman primates, it is important to determine if the
psychological and memory deficits associated with even moderate use of
MDMA recover after some period of time. This is a particularly
important issue with MDMA because of the relatively young age of the
majority of people who abuse this drug. So far, the majority of studies
have focused on MDMA users who have been abstinent for a period of a
few weeks to a few months - longer-term studies have been planned or
are underway - and these have shown that the adverse psychiatric and
cognitive changes associated with MDMA use are persistent.
In attempting to answer the question of whether MDMA causes permanent
damage to human memory abilities, there is no one study that provides a
resounding, definitive yes. To be sure, no study provides any evidence
that MDMA is a beneficial drug or even that it is safe when taken in
moderation. In fact taking MDMA at any dose carries with it the risk of
inducing physiological, psychological, and cognitive damage in
vulnerable users. Clearly, there is still room to debate the exact
nature of the deficits produced by MDMA use. Nevertheless, based on the
results from the overwhelming majority of studies conducted so far, the
data show that MDMA can be harmful to human health.
Methodological Issues
As much as the data collected so far largely supports the
proposition that MDMA damages the serotonin system in the brain and
produces long-lasting behavioral deficits, researchers agree that
methodological issues, such as limited sample size and difficulties
controlling for the possible influence of other illicit substances,
have made it difficult to move beyond generalities and unequivocally
prove a cause and effect relationship between MDMA use and specific
cognitive or psychological damage in humans.
All of the studies reviewed in this report have relied on self-referred
MDMA users, recruited through targeted sampling techniques by
advertising for volunteers or through word-of-mouth. This introduces an
unknown bias into each study since it is possible that such
self-referrers are not representative of MDMA users as a whole. There
is also the problem of verifying that what users report as Ecstasy is,
in fact, solely MDMA. In addition, it is impossible to verify
self-reports of past drug use beyond a certain period of time, making
it difficult at best to accurately control for prior drug use.
Since there seem to be few, if any, young people who use MDMA without
also abusing other drugs, this will continue to be a confounding factor
in future studies. Some investigators have tried to accommodate this
problem by using a control group comprising individuals who have never
used MDMA but who otherwise have closely matched histories of using
other drugs of abuse. This type of control has not been used
universally, however, and even when it is, it may be difficult to
closely match users and controls for prior drug use, as well as on
other demographic details such as educational level and age.
Self-reporting also means that it is not possible to determine with
complete confidence or accuracy how much a person has consumed, either
on a particular occasion or over a lifetime of use. This uncertainty
arises for two reasons: MDMA content is not constant across all
tablets, and user memory of how much and how often a person took MDMA
over many years is far from reliable.
Ideally, researchers would like to be able to study MDMA's effects in
drug-naïve humans, and indeed, a limited number of groups in Europe
have received approval from the appropriate governmental regulatory
agencies and institutional review boards to conduct what would
essentially be Phase I safety trials with MDMA in a limited number of
humans. However, there is little likelihood of studying the effects of
MDMA on large numbers of drug-naïve volunteers. An alternative might be
to conduct longitudinal, controlled prospective studies, in which
current MDMA users and controls of non-MDMA users are followed for many
years to observe changes from some defined baseline.
Challenges and Future Directions
Though the data presented at this conference and in the literature
support the hypothesis that MDMA produces acute behavioral and
physiological effects, there is still more to be determined about
factors that precipitate severe acute toxicity. For example, are there
predisposing genetic factors that increase the risk for acute toxicity?
Is overall health status important? Which organs and systems are the
primary targets of MDMA toxicity? Are interactions with other drugs
important? Does MDMA use lead to tolerance, withdrawal, and craving?
Because MDMA is not the only drug taken by young adults, there is a
need for more characterization of interactions between these substances
and a determination of how those drug interactions may influence acute
toxicity. Is the practice of "bumping" or taking sequential doses of
MDMA particularly dangerous? How do individual genetic factors
influence MDMA metabolism and drug interactions?
One critical piece of missing data is the incidence of acute toxicity
among MDMA users. Assembling this database will require improved
emergency room reporting of MDMA-associated incidents. In addition,
data do not yet exist on the number of people seeking treatment for
MDMA-related dependence and behavioral or psychological problems.
One of the key concerns raised at the meeting was the lack of
longitudinal studies designed to follow MDMA users, both as they
continue to use the drug and after they have stopped using it. Such
studies may provide important insight into how age and length of use
affect MDMA's acute and long-term neurochemical toxicity. In addition,
such studies would allow researchers to determine if deficits appear
later in life, long after use stops, or if adverse effects diminish
over time. Such studies, if designed with regular assessment intervals,
might also allow researchers to develop better measures of MDMA
toxicity, and to more accurately determine how much drug is used and in
what circumstances.
If conducted with large enough groups of MDMA users and control
subjects, both drug naïve and matched for poly-drug use, longitudinal
studies could also help identify risk and protective factors for drug
use and the deficits that result from continuing exposure to MDMA. The
identification of significant risk and protective factors would greatly
aid the development of efficacious prevention and rehabilitation
approaches. Data from longitudinal studies would also help establish
associations between MDMA use and behavioral impairments that
researchers have observed in the majority of studies.
Longitudinal designs may enable researchers to determine how long such
impairments last, whether they are progressive, and if deficits become
more evident as MDMA users move into middle and late adulthood or
experience other age-related neurologic disorders. Questions about the
reversibility of impairments, a concern given the data seen in animal
studies and even in some human studies, could also be addressed by such
designs. Longitudinal studies should also provide data on critical
patterns of MDMA use that may be more or less likely to cause
impairments, and can help to determine whether simultaneous abuse of
other drugs plays a role in causing behavioral and cognitive damage.
Along with such studies, researchers need better tools to assess
neurotoxicity in human MDMA users and to measure changes of neuronal
integrity and possible recovery over time. With such tools,
investigators may also be able to address important mechanistic
questions, such as how damage to the serotonin system leads to
behavioral and cognitive changes, how the brain responds to and
compensates for serotonergic damage, and why the dopaminergic system
seems to escape lasting damage from MDMA. Such studies might then lead
to the development and validation of methods for promoting recovery
from MDMA-induced neurotoxicity.
There is also a need for more studies looking at the long-term effects
of poly-drug abuse. Such studies will require new analytical tools for
detecting multiple drugs of abuse simultaneously in biological samples
and for more accurately assessing drug use histories, including the
combination and sequencing of drugs used.
There are little data available on whether addiction, dependence or
tolerance develops with continued use of MDMA. Though the data from
animal studies support this possibility, more studies are needed in
humans to determine the degree of abuse liability for this drug and to
help develop treatments specific for reducing MDMA addiction. Along the
same lines, researchers at this meeting stressed again that there are
little data on numbers of drug treatment patients who have used MDMA or
who have sought treatment because of MDMA abuse.
Another scientific gap idenitfied at the scientific conference
concerns the development of methods for tracking so-called hidden
populations of MDMA users; that is, those who don't go to dance clubs
or raves, where the majority of volunteer recruiting occurs. At the
same time, researchers also stressed the need to better understand the
youth party culture that seems to actively promote MDMA use through the
use of in-house drug dealers and marketing messages delivered through
music and by pop icons.
There is a need to foster interdisciplinary research and dialogue that
links epidemiological, ethnographic, clinical and laboratory studies.
As this report shows, there is much overlap between these separate
fields, and undoubtedly, this area of investigation could benefit from
better coordination between disciplines. There is also a need to link
local, regional, national, and international supply-side intelligence
with demand-side epidemiological and ethnographic research.
Prevention efforts cannot be universal but must be targeted at
different groups that use MDMA, particularly since MDMA appears to be a
drug whose use is sensitive to and intimately linked with social
context and networks. In particular, there is a need to integrate local
research, services, prevention and intervention efforts to provide
targeted, shared messages. The conference speakers recommended that
there be a new focus within youth networks and adult education programs
to counter the perception that MDMA is much safer than other drugs. The
use of youth-led advocacy and drug prevention programs seems
particularly promising for reducing MDMA use among adolescents and
young adults.
For related articles on Addiction
the Web, click on: “Sphere: Related Content” located at the bottom of this
blog post.
For related books or blog
posts with related content in Dr. Jeff’s and Dr. Tanya’s Blog, click on
the “Addictions: General” category at the bottom of the post or type in
keywords “Addiction” into “Google Search” located in the sidebar.
For related articles from
Psychology Today, click on the “Psychology Today” banner in the side bar
and type in Key words, “Addiction” into the Psychology Today “Search”.
For more books with related
content, click any hyperlinked key word in the blog or type in key words,
“Addiction“ into “Amazon Search” on the Amazon banner located in the side
bar.
Sources: National Institute of Drug Abuse; See also blogposts in: Addictions: Drug Abuse, and Psychiatry: Addictions: General
Many people do not understand why individuals become addicted to drugs
or how drugs change the brain to foster compulsive drug abuse. They
mistakenly view drug abuse and addiction as strictly a social problem
and may characterize those who take drugs as morally weak. One very
common belief is that drug abusers should be able to just stop taking
drugs if they are only willing to change their behavior. What people
often underestimate is the complexity of drug addiction—that it is a
disease that impacts the brain and because of that, stopping drug abuse
is not simply a matter of willpower. Through scientific advances we now
know much more about how exactly drugs work in the brain, and we also
know that drug addiction can be successfully treated to help people
stop abusing drugs and resume their productive lives.
Drug abuse
and addiction are a major burden to society. Estimates of the total
overall costs of substance abuse in the United States—including health-
and crime-related costs as well as losses in productivity—exceed half a
trillion dollars annually. This includes approximately $181 billion for
illicit drugs,1 $168 billion for tobacco,2 and $185 billion for alcohol.3
Staggering as these numbers are, however, they do not fully describe
the breadth of deleterious public health—and safety—implications, which
include family disintegration, loss of employment, failure in school,
domestic violence, child abuse, and other crimes.
What is drug addiction?
Addiction
is a chronic, often relapsing brain disease that causes compulsive drug
seeking and use despite harmful consequences to the individual who is
addicted and to those around them. Drug addiction is a brain disease
because the abuse of drugs leads to changes in the structure and
function of the brain. Although it is true that for most people the
initial decision to take drugs is voluntary, over time the changes in
the brain caused by repeated drug abuse can affect a person’s self
control and ability to make sound decisions, and at the same time send
intense impulses to take drugs.
It is because of these changes
in the brain that it is so challenging for a person who is addicted to
stop abusing drugs. Fortunately, there are treatments that help people
to counteract addiction’s powerful disruptive effects and regain
control. Research shows that combining addiction treatment medications,
if available, with behavioral therapy is the best way to ensure success
for most patients. Treatment approaches that are tailored to each
patient’s drug abuse patterns and any co-occurring medical,
psychiatric, and social problems can lead to sustained recovery and a
life without drug abuse.
Similar to other chronic, relapsing
diseases, such as diabetes, asthma, or heart disease, drug addiction
can be managed successfully. And, as with other chronic diseases, it is
not uncommon for a person to relapse and begin abusing drugs again.
Relapse, however, does not signal failure—rather, it indicates that
treatment should be reinstated, adjusted, or that alternate treatment
is needed to help the individual regain control and recover.
What happens to your brain when you take drugs?
Drugs
are chemicals that tap into the brain’s communication system and
disrupt the way nerve cells normally send, receive, and process
information. There are at least two ways that drugs are able to do
this: (1) by imitating the brain’s natural chemical messengers, and/or
(2) by overstimulating the “reward circuit” of the brain.
Some
drugs, such as marijuana and heroin, have a similar structure to
chemical messengers, called neurotransmitters, which are naturally
produced by the brain. Because of this similarity, these drugs are able
to “fool” the brain’s receptors and activate nerve cells to send
abnormal messages.
Other drugs, such as cocaine or
methamphetamine, can cause the nerve cells to release abnormally large
amounts of natural neurotransmitters, or prevent the normal recycling
of these brain chemicals, which is needed to shut off the signal
between neurons. This disruption produces a greatly amplified message
that ultimately disrupts normal communication patterns.
Nearly
all drugs, directly or indirectly, target the brain’s reward system by
flooding the circuit with dopamine. Dopamine is a neurotransmitter
present in regions of the brain that control movement, emotion,
motivation, and feelings of pleasure. The overstimulation of this
system, which normally responds to natural behaviors that are linked to
survival (eating, spending time with loved ones, etc.), produces
euphoric effects in response to the drugs. This reaction sets in motion
a pattern that “teaches” people to repeat the behavior of abusing drugs.
As
a person continues to abuse drugs, the brain adapts to the overwhelming
surges in dopamine by producing less dopamine or by reducing the number
of dopamine receptors in the reward circuit. As a result, dopamine’s
impact on the reward circuit is lessened, reducing the abuser’s ability
to enjoy the drugs and the things that previously brought pleasure.
This decrease compels those addicted to drugs to keep abusing drugs in
order to attempt to bring their dopamine function back to normal. And,
they may now require larger amounts of the drug than they first did to
achieve the dopamine high—an effect known as tolerance.
Long-term
abuse causes changes in other brain chemical systems and circuits as
well. Glutamate is a neurotransmitter that influences the reward
circuit and the ability to learn. When the optimal concentration of
glutamate is altered by drug abuse, the brain attempts to compensate,
which can impair cognitive function. Drugs of abuse facilitate
nonconscious (conditioned) learning, which leads the user to experience
uncontrollable cravings when they see a place or person they associate
with the drug experience, even when the drug itself is not available.
Brain imaging studies of drug-addicted individuals show changes in
areas of the brain that are critical to judgment, decisionmaking,
learning and memory, and behavior control. Together, these changes can
drive an abuser to seek out and take drugs compulsively despite adverse
consequences—in other words, to become addicted to drugs.
Why do some people become addicted, while others do not?
No
single factor can predict whether or not a person will become addicted
to drugs. Risk for addiction is influenced by a person’s biology,
social environment, and age or stage of development. The more risk
factors an individual has, the greater the chance that taking drugs can
lead to addiction. For example:
Biology.
The genes that people are born with––in combination with environmental
influences––account for about half of their addiction vulnerability.
Additionally, gender, ethnicity, and the presence of other mental
disorders may influence risk for drug abuse and addiction.
Environment.
A person’s environment includes many different influences––from family
and friends to socioeconomic status and quality of life in general.
Factors such as peer pressure, physical and sexual abuse, stress, and
parental involvement can greatly influence the course of drug abuse and
addiction in a person’s life.
Development.
Genetic and environmental factors interact with critical developmental
stages in a person’s life to affect addiction vulnerability, and
adolescents experience a double challenge. Although taking drugs at any
age can lead to addiction, the earlier that drug use begins, the more
likely it is to progress to more serious abuse. And because
adolescents’ brains are still developing in the areas that govern
decisionmaking, judgment, and self-control, they are especially prone
to risk-taking behaviors, including trying drugs of abuse.
Prevention is the Key
Drug
addiction is a preventable disease. Results from NIDA-funded research
have shown that prevention programs that involve families, schools,
communities, and the media are effective in reducing drug abuse.
Although many events and cultural factors affect drug abuse trends,
when youths perceive drug abuse as harmful, they reduce their drug
taking. It is necessary, therefore, to help youth and the general
public to understand the risks of drug abuse, and for teachers,
parents, and healthcare professionals to keep sending the message that
drug addiction can be prevented if a person never abuses drugs.
Sources: National Insittute of Mental Health, See also blogposts in: Addictions: Drug Abuse
Many substance abuse professionals wonder about the current
rate of prescription drug abuse in the United States. An article entitled,
“Misuse of prescription drugs is rising in the United States,” published in
Medscape (9/8/08) examines this issue. The article reviews a recent report from
the Substance Abuse and Mental Health Services Administration. The results of
the SAMHSA study were sobering. “Nonmedical use of prescription pain relievers
has risen 12% in the past year which included about 67,500 people across the
country…Drug use among those aged 55 to 59 years reportedly more than doubled,
to 4.1% in 2007. The survey suggests that baby boomers have continued their
higher levels of substance abuse as they age.” In addition, “in 2007, adults who had experienced a major depressive
episode in the past year were more than twice as likely as other adults to have
used drugs (27.4% vs12.8%).” The results of this study suggest that
prescription drug abuse and misuse, particularly of prescription pain
relievers, are increasing nationwide.
The Bottom Line:
The results of this study suggest that prescription drug abuse and misuse,
particularly of prescription pain relievers, are increasing nationwide.
For related articles on Addiction
the Web, click on: “Sphere: Related Content” located at the bottom of this
blog post.
For related books or blog
posts with related content in Dr. Jeff’s and Dr. Tanya’s Blog, click on
the “Addictions: General” category at the bottom of the post or type in
keywords “Addiction” into “Google Search” located in the sidebar.
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Psychology Today, click on the “Psychology Today” banner in the side bar
and type in Key words, “Addiction” into the Psychology Today “Search”.
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Sources: See blogposts in: Addictions: Drug Abuse, and Psychiatry: Addictions: General
Many parents of adolescents are interested in the risk of adolescent
prescription drug abuse. An article titled, “Screening Urged to Prevent
Prescription Drug Abuse,” published in Psychiatric News (8/15/08), examines
this issue. The article reports on a recent study from the Journal of the American Academy of Child and Adolescent
Psychiatry, in
which researchers surveyed 18,678 adolescents. The results of the study were
disturbing: “…one in 12 adolescents aged 12 to 17 (8.2 percent)
reported having misused at least one prescription medication in the
previous year. This prevalence trailed only the use of alcohol,
tobacco, and marijuana. Opioids such as
hydrocodone and oxycodone are by far the class of medications most
frequently misused by adolescents, followed by stimulants (for
example, amphetamines and methylphenidate), tranquilizers (including
benzodiazepines and muscle relaxants), and sedatives (for example,
barbiturates)…Prescription drug misuse among adolescents was
significantly linked to poor academic performance, a major
depressive episode in the past year, risk-taking tendencies, a
history of mental health treatment in the past year, and the concurrent use
of other substances, including cigarettes, alcohol, marijuana, cocaine, or
inhalants. Thirty-six percent of these adolescents who misused medications had symptoms that met one or more DSM-IV criteria for substance use disorder…Adolescent girls had a slightly higher prevalence
of misusing opioids, stimulants, and tranquilizers than did their
male peers.”
The Bottom Line: One in 12
adolescents aged 12 to 17 have misused at least one prescription medication in the past year, most commonly opioids such as hydrocodone
(Vicodin) and oxycodone (OxyContin).
For related articles on Addiction
the Web, click on: “Sphere: Related Content” located at the bottom of this
blog post.
For related books or blog
posts with related content in Dr. Jeff’s and Dr. Tanya’s Blog, click on
the “Addictions: General” category at the bottom of the post or type in
keywords “Addiction” into “Google Search” located in the sidebar.
For related articles from
Psychology Today, click on the “Psychology Today” banner in the side bar
and type in Key words, “Addiction” into the Psychology Today “Search”.
For more books with related
content, click any hyperlinked key word in the blog or type in key words,
“Addiction“ into “Amazon Search” on the Amazon banner located in the side
bar.
Sources: See blogposts in: Addictions: Drug Abuse, and Psychiatry: Adolescents and Young Adults
