Important Information about
Substance Use Science
Substance Abuse is
defined as a chronic, relapsing brain disease that is characterized by
compulsive drug seeking and use, despite harmful consequences. When substance abuse began to be studied in the 1930s, people misusing alcohol or other drugs were thought to be morally flawed and lacking in willpower.
Now research tells us that severe substance misuse is a brain disease because
drugs change the brain—they change its structure and how it works. These brain
changes can be long lasting, and can lead to the harmful behaviors seen in
people who abuse drugs.
Abuse of alcohol, nicotine, and
illegal substances cost Americans upwards of
half a trillion dollars a year,
considering their combined medical, economic, criminal, and social impact. Every year, abuse of illicit drugs and alcohol
contributes to the death of more than 100,000 Americans, while tobacco is
linked to an estimated 440,000 deaths per year.
factors increase risk of developing a substance abuse problem? Scientists
estimate that genetic factors account for between 40-60% of a
person’s vulnerability to substance misuse, including the effects of environment on
gene expression and function. Adolescents and individuals with mental disorders
are at greater risk of drug abuse than the general population.
Introducing the Human
Brain The human brain is the
most complex organ in the body. This three-pound mass of gray and white matter
sits at the center of all human activity—you need it to drive a car, to enjoy a
meal, to breathe, to create an artistic masterpiece, and to enjoy everyday activities.
In brief, the brain regulates your basic body functions; enables you to
interpret and respond to everything you experience; and shapes your thoughts,
emotions, and behavior.
The brain is made up of many
parts that all work together
as a team. Different parts of the brain are responsible for coordinating and
performing specific functions. Drugs can alter important brain areas that are
necessary for life-sustaining functions and can drive the compulsive drug abuse
that marks addiction. Brain areas affected by drug abuse:
1. The Brain Stem controls basic
functions critical to life, such as heart rate, breathing, and sleeping.
2. The Limbic System contains the
brain’s reward circuit—it links together a number of brain structures that
control and regulate our ability to feel pleasure. Feeling pleasure motivates
us to repeat behaviors such as eating—actions that are critical to our
existence. The limbic system is activated when we perform these activities— and
also by drugs of abuse. In addition, the limbic system is responsible for our
perception of other emotions, both positive and negative, which explains the
mood-altering properties of many drugs.
3. The Cerebral Cortex is divided
into areas that control specific functions. Different areas process information from our senses, enabling us to see,
feel, hear, and taste. The front part of the cortex, the frontal cortex or
forebrain, is the thinking center of the brain; it powers our ability to think,
plan, solve problems, and make decisions.
How does the brain communicate? The brain is a communications center
consisting of billions of neurons, or nerve cells. Networks of neurons
pass messages back and forth to different structures within the brain, the
spinal column, and the peripheral nervous system. These nerve networks
coordinate and regulate everything we feel, think, and do.
1. Neuron to Neuron Each nerve cell in the brain
sends and receives messages in the form of electrical impulses. Once a cell
receives and processes a message, it sends it on to other neurons.
Brain’s Chemical Messengers The
messages are carried between neurons by chemicals called neurotransmitters.
(They transmit messages between neurons.)
3. Receptors—The Brain’s
Chemical Receivers The
neurotransmitter attaches to a specialized site on the receiving cell called a
receptor. A neurotransmitter and its receptor operate like a “key and lock,” an
exquisitely specific mechanism that ensures that each receptor will forward the
appropriate message only after interacting with the right kind of
Brain’s Chemical Recyclers Located
on the cell that releases the neurotransmitter, transporters recycle these
neurotransmitters (i.e., bring them back into the cell that released them), thereby
shutting off the signal between neurons.
To send a message a brain cell releases a chemical
(neurotransmitter) into the space separating two cells called the synapse. The neurotransmitter crosses the synapse and
attaches to proteins (receptors) on the receiving brain cell. This causes
changes in the receiving brain cell and the message is delivered.
How do drugs work in
chemicals. They work in the brain by tapping into the brain’s communication
system and interfering with the way nerve cells normally send, receive, and
process information. Some drugs, such as marijuana and heroin, can activate
neurons because their chemical structure mimics that of a natural
neurotransmitter. This similarity in structure “fools” receptors and allows the
drugs to lock onto and activate the nerve cells. Although these drugs mimic
brain chemicals, they don’t activate nerve cells in the same way as a natural
neurotransmitter, and they lead to abnormal messages being transmitted through
Other drugs, such as amphetamine or cocaine, can cause
the nerve cells to release abnormally large amounts of natural neurotransmitters
or prevent the normal recycling of these brain chemicals. This disruption
produces a greatly amplified message, ultimately disrupting communication
channels. The difference in effect can be described as the difference between
someone whispering into your ear and someone shouting into a microphone.
How do drugs work in
the brain to produce pleasure? Most
drugs of abuse 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 regulate movement, emotion, cognition, motivation, and feelings
of pleasure. The over stimulation of this system, which rewards our natural
behaviors, produces the euphoric effects sought by people who abuse drugs and
teaches them to repeat the behavior.
How does stimulation of
the brain’s pleasure circuit teach us to keep taking drugs? Our brains are wired to ensure
that we will repeat life-sustaining activities by associating those activities
with pleasure or reward. Whenever this reward circuit is activated, the brain
notes that something important is happening that needs to be remembered, and
teaches us to do it again and again, without thinking about it. Because drugs
of abuse stimulate the same circuit, we learn to abuse drugs in the same way.
Brain Reward (Dopamine) Pathways These
brain circuits are important for natural rewards such as food, music, and sex. Drugs of abuse increase dopamine
What happens to your
brain if you keep taking drugs? Just
as we turn down the volume on a radio that is too loud, the brain adjusts to
the overwhelming surges in dopamine (and other neurotransmitters) by producing
less dopamine or by reducing the number of receptors that can receive signals.
As a result, dopamine’s impact on the reward circuit of a drug abuser’s brain
can become abnormally low, and the ability to experience any pleasure is
reduced. This is why the abuser eventually feels flat, lifeless, and depressed,
and is unable to enjoy things that previously brought them pleasure. Now, they
need to take drugs just to try and bring their dopamine function back up to
normal. And, they must take larger amounts of the drug than they first did to
create the dopamine high—an effect known as tolerance.
What are the medical
consequences of drug addiction? Individuals
who suffer from addiction often have one or more accompanying medical issues,
including lung and cardiovascular disease, stroke, cancer, and mental
disorders. Imaging scans, chest X-rays, and blood tests show the damaging
effects of drug abuse throughout the body. For example, tests show that tobacco
smoke causes cancer of the mouth, throat, larynx, blood, lungs, stomach,
pancreas, kidney, bladder, and cervix. In addition, some drugs of abuse, such
as inhalants, are toxic to nerve cells and may damage or destroy them either in
the brain or the peripheral nervous system.
drug abuse cause mental disorders, or vice versa? Drug
abuse and mental disorders often co-exist. In some cases, mental diseases may
precede addiction; in other cases, drug abuse may trigger or exacerbate mental
disorders, particularly in individuals with specific vulnerabilities.
Important Information about
Central Nervous System Depressants These substances produce a sedative and anxiety-reducing
effect, which can lead to dependence. These drugs include:
(amobarbital, pentobarbital, secobarbital, "yellow
(Valium, Ativan, Xanax)
Signs and symptoms of alcohol or other depressant use:
- Lack of coordination
- Decreased attention span
- Impaired judgment
- Slurred speech
- Lower inhibitions
- Affected thoughts,
emotions and judgment
domestic problems, poor performance at work or school
- Increased likelihood of
committing violent crimes, drowning, suicides and homicides, unprotected sex, & sexual abuse or rape
problems caused by excessive use:
- Liver disease
- Digestive problems such as gastritis, ulcers, or
- Heart problems like high blood pressure, heart failure, or
complications such as hypoglycemia
function and menstruation problems
problems such as involuntary rapid eye movement as well as weakness and
paralysis of your eye
defects may be caused by a pregnant woman drinking alcohol
loss like osteoporosis
complications that affect your speech, cause pain in your hands & feet,
dementia and memory loss
immune system making you more susceptible to illnesses and possible death
risk of cancer such as mouth, throat, liver, colon and breast cancer
- Overdose or death
Marijuana Marijuana is also called "pot," "reefer," "joint," "weed," "blunt". Marijuana comes from a plant called hemp. The main,
active ingredient is THC. This and other ingredients, called cannabinoids, are found in the leaves and
flowering parts of the marijuana plant. Marijuana
acts on your central nervous system. Low-to-moderate amounts of the drug may
appetite ("the munchies")
of joy (euphoria)
sensations of sight, hearing, and taste
of panic, or rarely severe paranoia
ability to perform tasks that require a lot of coordination (such as driving)
interest in completing tasks
- Delirium or seeing or hearing things that aren't there
heart rate and blood pressure
such as sinusitis, bronchitis, and asthma in heavy users
of the airways causing narrowing or spasms
weakening of the immune system
concentrating and paying attention, which can interfere with learning
users may have withdrawal effects when they stop marijuana use. These may
include: Agitation, Insomnia, Irritability.
Medical Marijuana THC has been approved by the U.S. Food and
Drug Administration (FDA) for the following medical purposes:
chronic pain and spasticity
appetite in patients with AIDS or who have undergone chemotherapy
- Treating glaucoma
nausea caused by chemotherapy in cancer patients
Opiates, Opioids, and Narcotics Opiates come from opium poppies. These drugs include
morphine and codeine. Opioids are artificial substances that have the same
effect as morphine or codeine. The term "narcotic" refers to either
type of drug. Narcotics are powerful
painkillers that cause drowsiness (sedation) and sometimes, feelings of
euphoria. These drugs include:
(Percocet or Oxycontin)
and symptoms of narcotic use:
respiratory depression leading to coma, and death in high doses
marks on the skin ("tracks") if drug use is by injection
or euphoric state
from skin abscesses if drug use is by injection
heroin is commonly injected into a vein (used intravenously), there are health
concerns about sharing contaminated needles among IV drug users. Complications
of sharing contaminated needles include hepatitis. HIV infection, and AIDS.
Cocaine The abuse of cocaine increased
dramatically in the late 1980s and early 1990s, but is now on the decline.
Other names to describe different forms of cocaine include "crack,"
"coke," "snow," and "speedball."
may be taken in different ways:
Inhaling it through the nose
up: Dissolving it in water and injected it into a vein
Mixed with heroin and shot into a vein
Cocaine may be changed into a smokeable form known as freebase or crack
cocaine produces a nearly instant and intense sense of joy (euphoria), which is
attractive to abusers. Other effects include:
of increased confidence and energy
stimulation of the central nervous system
users of cocaine may need larger amounts of the drug to feel these effects.
Regular users of cocaine may have:
of interest in school, work, family, and friends
use may cause paranoia, which can lead to violence.
Phencyclidine (PCP) PCP is an illegal drug that comes
as a white powder, which can be dissolved in alcohol or water. PCP may be smoked, shot into a vein, or
taken by mouth. How quickly it affects you depends on how you take it.
up: If given through a vein, PCP's effects start within 2-5 minutes.
The effects begin within 2 - 5 minutes, peaking at 15 - 30 minutes.
by mouth: In pill form, or mixed with food or drinks, PCP's effects usually
start within 30 minutes. The effects tend to peak in about 2 - 5 hours.
doses of PCP will cause different effects:
doses of PCP typically produce feelings of joy (euphoria) and less inhibition,
similar to being drunk.
doses cause numbness throughout the body, and perception changes that may lead
to extreme anxiety and violence.
doses may produce paranoia, "hearing voices" (auditory
hallucinations), and psychosis similar to schizophrenia.
doses, usually from taking the drug by mouth, may cause acute kidney failure, heart arrhythmias, muscle rigidity, seizures, and even death.
of the pain-killing properties of PCP, users who get seriously injured may not
feel any pain.
Club Drugs A number of other illegal drugs have become popular recently. Their use causes changes in perception and/or loss of memory.
- Ketamine (related to PCP) called "Special K"
- MDMA or "Ecstasy"
and Rohypnol, also called "date rape drug"
LSD and other Hallucinogens LSD (lysergic acid diethylamide) is a very strong
hallucinogen. Only tiny amounts are needed to cause effects, such as
hallucinations. Other commonly abused hallucinogens are Psilocybin
(mushrooms, "shrooms") and Peyote
(a cactus plant containing mescaline). LSD use may cause Anxiety, Blurred vision, Paranoid delusions, Seeing things that aren't there. Hallucinogens
can lead to extreme anxiety and lack of reality, called "bad trips". These experiences can come back as a "flashback," even without using
the drug again. Such experiences typically occur during times of increased
stress, and tend to occur less often and intensely after stopping the drugs.
are stimulants. Other names used to describe amphetamines or methamphetamines
include "meth", "crystal", "uppers", go", or "crank". Amphetamines
are very addictive. Prescription amphetamines are considered controlled
substances. Over-the-counter amphetamine look-alike drugs are often
abused. These drugs typically contain caffeine and other stimulants, and are sold as appetite suppressants
or stay-awake/stay-alert aids. Signs & symptoms of stimulant use:
feeling of well-being (euphoria)
- Sores from scratching
- Dental problems
use became popular with young teens in the 1960s with "glue
sniffing." Since then, a greater variety of inhalants have become popular.
Inhalant use typically involves younger teens or school-age children. Commonly abused inhalants include: Aerosols for deodorants or hair sprays, Cleaning fluids, Gasoline, Liquid typewriter correction fluid, Model glue, Spray paints.
Negative effects of inhalant abuse include:
- Brain damage
- Liver or kidney damage
- Nerve damage
- Sudden death