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Effects of Depressants on the Brain and the Central Nervous System Back to Course Index

Effects of Depressants on the Brain and Central Nervous System

(Part 1 in a series on the Central Nervous System and Drugs)



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. The major areas of the brain are as follows:


        The brain stem controls basic functions critical to life, such as heart rate, breathing, and sleeping;

        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.


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.



The Central Nervous System (CNS)

The CNS coordinates the functions of all parts of the body and consists of the brain and the spinal cord, as well as the retina. Together with the Peripheral Nervous System (PNS), it has a fundamental role in the control of behavior. The CNS is contained within the dorsal cavity, with the brain in the cranial cavity and the spinal cord in the spinal cavity.  The brain is protected by the skull, while the spinal cord is protected by the vertebrae, and both are enclosed in the meninges. 

The brain receives sensory input from the spinal cord as well as from its own nerves (e.g., olfactory and optic nerves) and devotes most of its volume to processing its various sensory inputs and initiating appropriate and coordinated motor outputs.  Whereas, the spinal cord conducts sensory information from the PNS to the brain and transmits motor information from the brain to various effectors such as skeletal muscles, cardiac muscle, and various glands.

The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions and transmit signals between different parts of the body.  The peripheral nervous system consists of sensory neurons, clusters of neurons called ganglia, and nerves connecting them to each other and to the central nervous system. These regions are all interconnected by means of complex neural pathways.

Neurons send signals to other cells as electrochemical waves travelling along thin fibers called axons, which cause chemicals called neurotransmitters to be released at junctions called synapses. A cell that receives a synaptic signal may be excited, inhibited, or otherwise modulated. Sensory neurons are activated by physical stimuli impinging on them, and send signals that inform the central nervous system of the state of the body and the external environment. Motor neurons situated either in the central nervous system or in peripheral ganglia, connect the nervous system to muscles or other effecter organs. Central neurons, which in vertebrates greatly outnumber the other types, make all of their input and output connections with other neurons. The interactions of all these types of neurons form neural circuits that generate an organism’s perception of the world and determine its behavior.

The brain and nervous system are made of billions of nerve cells, called neurons. Neurons have three main parts: cell body, dendrites, and axon. The axon is covered by the myelin sheath. The transfer of information between neurons is called neurotransmission. This is how neurotransmission works:

  1. A message travels from the dendrites through the cell body and to the end of the axon;
  2. The message causes the chemicals, called neurotransmitters, to be released from the end of the axon into the synapse. The neurotransmitters carry the message with them into the synapse. The synapse is the space between the axon of one neuron and the dendrites of another neuron;
  3. The neurotransmitters then travel across the synapse to special places on the dendrites of the next neuron, called receptors. The neurotransmitters fit into the receptors like keys in locks;
  4.  Once the neurotransmitter has attached to the receptors of the second neuron, the message is passed on;
  5. The neurotransmitters are released from the receptors and are either broken down or go back into the axon of the first neuron.


At the most basic level, the CNS sends signals from one cell to another or from one part of the body to another part. There are multiple ways that a cell can send signals to other cells. One is by releasing chemicals called hormones into the internal circulation, so that they can diffuse to distant sites. In contrast to this “broadcast” mode of signaling, the nervous system provides “point-to-point” signals where neurons project their axons to specific target areas and make synaptic connections with specific target cells. Thus, neural signaling is capable of a much higher level of specificity than hormonal signaling. It is also much faster: the fastest nerve signals travel at speeds that exceed 100 meters per second.

At a more integrative level, the primary function of the nervous system is to control the body.  It does this by extracting information from the environment using sensory receptors, sending signals that encode this information into the central nervous system, processing the information to determine an appropriate response, and sending output signals to muscles or glands to activate the response. The evolution of a complex nervous system has made it possible for various animal species to have advanced perception abilities such as vision, complex social interactions, rapid coordination of organ systems, and integrated processing of concurrent signals. In humans, the sophistication of the nervous system makes it possible to have language, abstract representation of concepts, transmission of culture, and many other features of human society that would not exist without the human brain.

This continuing education course will focus on the area of psychoactive chemicals and the central nervous system.  The term psychoactive chemical simply means that a chemical has the capability to increase or decrease the speed of electrical impulses along the nervous system.  This is accomplished simply by altering the various bio-chemicals or neurotransmitters at the neuronal gaps or synapses.  For example, alcohol slows down this electrical activity while cocaine speeds up this electrical activity.

This course will address CNS Depressants.  Subsequent courses will cover other drugs. 




Psychoactive chemicals may be distinguished by their overall effects on the CNS.  The classifications of depressants, stimulants, psychedelics, and others (inhalants, prescription drugs, etc.) are commonly used.  Psychoactive chemicals act on the brain by affecting various neurotransmitters (neurotransmitters are brain chemicals that facilitate communication between brain cells).  For example, CNS depressants act on the neurotransmitter gamma amino butyric acid (GABA).  GABA works by decreasing brain activity. Although the different classes of CNS depressants work in unique ways, it is through their ability to increase GABA activity that they produce a drowsy or calming effect that is beneficial to those suffering from anxiety or sleep disorder.  Other classifications act on different neurotransmitters that are identified and discussed in later sections of this continuing education course.



CNS DEPRESSANTS (Excerpts were taken from the NIDA website)

CNS depressants are substances that can slow normal brain functions and alter others.  For example, they slow heart rate and respiration, relax muscles, decrease coordination, induce sleep and dull the senses (reduce pain). Because of these properties, some depressants are useful in the treatment of anxiety and sleep disorders. The major categories of depressants are:

         Sedatives, hypnotics, and Anxiolytics:   Barbiturates and Benzodiazepines are the major substances in this classification and have the following applications and characteristics.  Barbiturates, such as mephobarbital (Mebaral) and pentobarbital sodium (Nembutal), are used to treat anxiety, tension, and sleep disorders and Benzodiazepines, such as diazepam (Valium), chlordiazepoxide HCl (Librium), and alprazolam (Xanax), are prescribed to treat anxiety, acute stress reactions, and panic attacks. The more sedating benzodiazepines, such as triazolam (Halcion) and estazolam (ProSom) are prescribed for short-term treatment of sleep disorders. Usually, benzodiazepines are not prescribed for long-term use.  Another benzodiazepine that has been the focus of a great deal of media attention is flunitrazepam, trade name Rohypnol, which is known widely as a date-rape drug” due to its involvement in many sexual assault cases in recent years.

         Opiates/Opioids/Narcotics/Heroin: Prototype narcotic (pain killer) is morphine that is extracted from opium.  Opiates are derived from resin of the poppy plant.  The resin can be converted to opium, codeine, and morphine.  Medical use is to relieve pain.  

         Alcohol: Ethyl alcohol contained in liquors, wine, beer, and similar alcoholic products. The major application for alcoholic beverages is for self-medication.

Sedatives, Hypnotics and Anxiolytics

Despite their many beneficial effects, barbiturates and benzodiazepines have the potential for abuse and should be used only as prescribed by a medical professional. During the first few days of taking a prescribed CNS depressant, a person usually feels sleepy and uncoordinated, but as the body becomes accustomed to the effects of the drug, these feelings begin to disappear. If one uses these drugs long term, the body will develop tolerance for the drugs, and larger doses will be needed to achieve the same effects as was felt at their initial use. Continued use can lead to physical dependence and – when use is reduced or stopped – withdrawal. Because all CNS depressants work by slowing the brain’s activity, when an individual stops taking them, the brain’s activity can rebound and race out of control, potentially leading to seizures and other harmful consequences. Although withdrawal from benzodiazepines can be problematic, it is rarely life threatening, whereas withdrawal from prolonged use of other CNS depressants can cause life-threatening complications. Therefore, someone who is thinking about discontinuing CNS depressant therapy or who is suffering withdrawal from a CNS depressant should seek medical treatment. 

Barbiturates make people very relaxed, calm, and sleepy. These drugs are sometimes used to help patients relax before surgery. Some may also be used to control seizures (convulsions).  Barbiturates have generally been replaced by other medicines for treatment of nervousness and sleep disorder.  However, some are still used in anesthesiology to induce anesthesia and lower the dose of inhaled anesthetics required for surgical procedures.  For example, Pentobarbital (Nembutal) has been used in neurosurgery to reduce blood flow to the brain. This reduces swelling and pressure in the brain, making brain surgery safer. Secobarbital (Seconal) may be given by mouth or as a suppository to induce sleepiness and relaxation before local anesthesia or the insertion of a tube into the nose or throat.  These medicines may become habit-forming and should not be used to relieve everyday anxiety and tension or to treat sleeplessness over long periods.

CNS depressants should not be used in combination with other medications except under a physician’s supervision. Typically, they should not be combined with any other medication or substance that causes CNS depression, including prescription pain medicines, some Over-The-Counter (OTC) cold and allergy medications, and alcohol. Using CNS depressants with these other substances – particularly alcohol – can slow both the heart and respiration and may lead to death.

Small doses slow heart rate and respiration, decrease coordination, relax muscles, induce sleep and dull the senses.  User may exhibit drunken behavior (slurred speech, staggering and drowsiness), confusion, faulty judgment, emotional instability, hostility and paranoid ideas.



Opiates are used medically to relieve pain.  Opiates are constituents found in opium, which is processed from the resin of the poppy plant.  Semi-synthetic opioids such as heroin, oxycodone and hydrocodone are derived primarily from morphine, codeine and trebaine.  Some common prescription painkillers (e.g., OxyContin, Vicodin, and Fentanyl) are also classified as opiates. They act on specific (opiate) receptors in the brain, which also interact with naturally produced substances known as endorphins or enkephalins important in regulating pain and emotion. And while prescription painkillers are highly beneficial medications when used as prescribed, opiates as a general class of drugs have significant abuse liability. Some of these drugs are sometimes referred to as narcotics because they are habit forming, dull the senses, relieves pain and induces sleepiness. 

Opiates are found in a variety of forms including powders, liquids, tablets, and capsules.  Some opiates, such as codeine, meperidine, morphine and dilaudid are prescribed by a physician to relieve pain, cough, or diarrhea.  Other applications are as follows:

         Codeine:  Relieves moderate pain; frequently abused prescription drug

         Morphine: Morphine is a potent opiate analgesic and is considered to be the prototypical opioid.  In clinical medicine, morphine is used to relieve severe or agonizing pain and suffering. Like other opioids, (e.g. oxycodone (OxyContin, Percocet, Percodan), hydromorphone (Dilaudid, Palladone), and diacetylmorphine (heroin), morphine acts directly on the CNS to relieve pain. Morphine results in a sense of well-being, causes drowsiness, mental clouding and changes in mood.  It has a high potential for addiction; tolerance and both physical and psychological dependence develop rapidly.

         Meperidine: Meperidine is a short acting analgesic used to treat moderate to severe pain.  It is less potent than morphine.

         Hydromorphone (dilauded): Dilaudid is a short acting semi-synthetic opioid used to relieve moderate to severe pain.  It is approximately eight times more powerful than morphine.

         Fentanyl: Fentanyl brand names include Sublimaze, Actiq, Durogesic, Duragesic, Fentora, and others.  It is a potent narcotic analgesic with a rapid onset and short duration of action. Historically it has been used to treat severe pain and is approximately 100 times more potent than morphine.  Fentanyl is used intravenously during surgical procedures and it may also be smoked or snorted (non-medical applications).  In the 1980s clandestine labs began manufacturing fentanyl derivatives or analogues which mimic the effects of heroin and morphine.  The most common analogue is known as Chine White (Schedule I list of controlled substances).

         Herion:  Heroin is an opiate drug that is synthesized from morphine, a naturally occurring substance extracted from the seed pod of the Asian poppy plant. Heroin usually appears as a white or brown powder or as a black sticky substance, known as black tar heroin.  Heroin can be injected, snorted/sniffed, or smoked. Injecting is the use of a needle to administer the drug directly into the bloodstream. Snorting is the process of inhaling heroin powder through the nose, where it is absorbed into the bloodstream through the nasal tissues. Smoking involves inhaling heroin smoke into the lungs. All three methods of administering heroin can lead to addiction and other severe health problems. Heroin enters the brain, where it is converted to morphine and binds to receptors known as opioid receptors. These receptors are located in many areas of the brain (and in the body), especially those involved in the perception of pain and in reward. Opioid receptors are also located in the brain stem (important for automatic processes of critical for life functions, such as breathing, regulating blood pressure, and arousal. Heroin overdoses frequently involve a suppression of respiration.  After an intravenous injection of heroin, users report feeling a surge of euphoria (rush) accompanied by dry mouth, a warm flushing of the skin, heaviness of the extremities, and clouded mental functioning. Following this initial euphoria, the user goes on the nod, an alternately wakeful and drowsy state. Users who do not inject the drug may not experience the initial rush, but other effects are the same.  With regular heroin use, tolerance develops, in which the users physiological (and psychological) response to the drug decreases, and more heroin is needed to achieve the same intensity of effect. Heroin users are at high risk for addiction. It is estimated that approximately 25 percent of individuals who use heroin become dependent on it.

Heroin abuse is associated with serious health conditions, including fatal overdose, spontaneous abortion, and particularly in users who inject the drug infectious diseases, including HIV/AIDS and hepatitis. Chronic users may develop collapsed veins, infection of the heart lining and valves, abscesses, and liver or kidney disease. Pulmonary complications, including various types of pneumonia, may result from the poor health of the abuser as well as from heroine depressing effects on respiration. In addition to the effects of the drug itself, street heroin often contains toxic contaminants or additives that can clog blood vessels leading to the lungs, liver, kidneys, or brain, causing permanent damage to vital organs.  Chronic use of heroin leads to physical dependence, a state in which the body has adapted to the presence of the drug. If a dependent user reduces or stops use of the drug abruptly, he or she may experience severe symptoms of withdrawal. These symptoms which can begin as early as a few hours after the last drug administration can include restlessness, muscle and bone pain, insomnia, diarrhea and vomiting, cold flashes with goose bumps (cold turkey), and kicking movements (kicking the habit). Users also experience severe craving for the drug during withdrawal, which can precipitate continued abuse and/or relapse. Major withdrawal symptoms peak between 48 and 72 hours after the last dose of the drug and typically subside after about 1 week. Some individuals, however, may show persistent withdrawal symptoms for months. Although heroin withdrawal is considered less dangerous than alcohol or barbiturate withdrawal, sudden withdrawal by heavily dependent users who are in poor health is occasionally fatal. In addition, heroin craving can persist years after drug cessation, particularly upon exposure to triggers such as stress or people, places, and things associated with drug use.

Heroin abuse during pregnancy, together with related factors like poor nutrition and inadequate prenatal care, has been associated with adverse consequences including low birth weight, an important risk factor for later developmental delay. If the mother is regularly abusing the drug, the infant may be dependent on heroin at birth and could suffer from serious medical complications.

A range of treatments exist for heroin addiction, including medications and behavioral therapies. Science has taught us that when medication treatment is combined with other supportive services, patients are often able to stop using heroin (or other opiates) and return to stable and productive lives. Treatment usually begins with medically assisted detoxification to help patients to safely eliminate the drug from their body. Medications such as clonidine and buprenorphine can be used during detoxification to help the patient stabilize during this process. However, detoxification alone is not treatment and has not been shown to be effective in preventing relapse.  It is merely the first step.

Methadone has been used for more than 40 years to treat heroin addiction. It is a synthetic opiate medication that binds to the same receptors as heroin; but when taken orally, it has a gradual onset of action and sustained effects, reducing the desire for other opioid drugs while preventing withdrawal symptoms. Properly administered, methadone is not intoxicating or sedating, and its effects do not interfere with ordinary daily activities. Methadone maintenance treatment is usually conducted in specialized opiate treatment programs. The most effective methadone maintenance programs include individual and/or group counseling, as well as provision of or referral to other needed medical, psychological, and social services. Administered daily, methadone treatment is currently regulated so that only specialized clinics can provide it.

Naltrexone, an opioid receptor blocker, joined the medications inventory in 1980s. It proved to be highly effective in reversing the effects of opiate overdose, but poor treatment adherence has hampered its utility to promote abstinence.  Naltrexone as a treatment for opioid addiction is usually prescribed in outpatient medical settings, although initiation of the treatment often begins after medical detoxification in a residential setting. To prevent withdrawal symptoms, individuals must be medically detoxified and opioid-free for several days before taking naltrexone.

Buprenorphine is a more recently approved treatment for heroin addiction (and other opiates). Buprenorphine is a long-acting partial agonist that acts on the same receptors as heroin and morphine, relieving drug cravings without producing the same intense “high” or dangerous side effects. These medications, along with effective behavioral treatments and outreach efforts, have not only reduced injection drug use in this country, but have also helped reduce the spread of HIV/AIDS from a peak of more than 25,000 new cases in 1993 to fewer than 10,000 cases in 2003.  Compared with methadone, buprenorphine produces less risk for overdose and withdrawal effects and produces a lower level of physical dependence, so patients who discontinue the medication generally have fewer withdrawal symptoms than those who stop taking methadone. The development of buprenorphine and its authorized use in physicians offices give opiate-addicted patients more medical options and extend the reach of addiction medication. Its accessibility may even prompt attempts to obtain treatment earlier. However, not all patients respond to buprenorphine some continue to require treatment with methadone.

For pregnant heroin abusers, methadone maintenance combined with prenatal care and a comprehensive drug treatment program can improve many of the detrimental maternal and neonatal outcomes associated with untreated heroin abuse. Preliminary evidence suggests that buprenorphine may also be a safe and effective treatment during pregnancy, although infants exposed to either methadone or buprenorphine prenatally may still require treatment for withdrawal symptoms. For women who do not want or are not able to receive pharmacotherapy for their heroin addiction, detoxification from opiates during pregnancy can be accomplished with medical supervision, although potential risks to the fetus and the likelihood of relapse to heroin use should be considered.

There are several effective behavioral treatments available for heroin addiction usually in combination with medication. These can be delivered in residential or outpatient settings. Examples are individual or group counseling; contingency management, which uses a voucher-based system where patients earn points based on negative drug tests.  These points can be exchanged for items that encourage healthy living; and cognitive-behavioral therapy, designed to help modify a patients expectations and behaviors related to drug abuse, and to increase skills in coping with various life stressors.

In 2009, 605,000 Americans age 12 and older had abused heroin at least once in the year prior to being surveyed. Source: National Survey on Drug Use and Health (Substance Abuse and Mental Health Administration Web Site). The NIDA-funded 2010 Monitoring the Future Study showed that 0.8% of 8th graders, 0.8% of 10th graders, and 0.9% of 12th graders had abused heroin at least once in the year prior to being surveyed. Source: Monitoring the FutureExternal link, please review our disclaimer. (University of Michigan Web Site). Currently, approximately 1 million people in the United States are addicted to heroin (Office of National Drug Control Policy, 2000).  


Alcohol is the oldest and best known drug used in the world and it is legal for adults to consume alcoholic beverages in most counties of the world.  Almost half of all adult Americans are consumers of alcohol.  Most individuals do not have a problem with alcoholism; however, there are an estimated 12 to 16 million alcoholics or problem drinkers in the United States.  Also, there are over 100,000 deaths attributed to alcohol misuse each year.  What most Americans dont realize is that among the nations alcoholics and problem drinkers are as many as 5 million adolescents.

Alcohol (technically ethyl alcohol or ethanol) is an intoxicating ingredient found in beer, wine, and liquor and is produced by the fermentation of yeast, sugars, and starches. It is rapidly absorbed from the stomach and small intestine into the bloodstream. A standard drink equals 0.6 ounces of pure ethanol, or 12 ounces of beer; 8 ounces of malt liquor; 5 ounces of wine; or 1.5 ounces (a “shot”) of 80-proof distilled spirits or liquor (e.g., gin, rum, vodka, or whiskey).  There are three basic types of alcoholic beverages:

Beer: Made from fermented grains and has an alcoholic content of from three to six percent.

Wine: Made from fermented fruits and have an alcohol content of from 11 to 14 percent.                                           Fortified wines such as port, have alcohol added, bringing the alcohol content to                          between 18 and 20 percent. 

Liquor:  Made by distilling a fermented product and contains a 40 to 50 percent alcohol.  The alcohol content in liquor is half the proof.  Thus, 80 proof liquor is 40 percent alcohol.


Statistics and Trends

In 2009, 51.9% of Americans age 12 and older had used alcohol at least once in the 30 days prior to being surveyed; 23.7% had binged (5+ drinks within 2 hours); and 6.8% drank heavily (5+ drinks on 5+ occasions). In the 12-17 age range, 14.7% had consumed at least one drink in the 30 days prior to being surveyed; 8.8% had binged; and 2.1% drank heavily. Source: National Survey on Drug Use and Health (Substance Abuse and Mental Health Administration Web Site). The NIDA-funded 2010 Monitoring the Future Study showed that 13.8% of 8th graders, 28.9% of 10th graders, and 41.2% of 12th graders had consumed at least one drink in the 30 days prior to being surveyed, and 5.0% of 8th graders, 14.7% of 10th graders, and 26.8% of 12th graders had been drunk. Source: Monitoring the FutureExternal link, please review our disclaimer. (University of Michigan Web Site).


Physiological Effects

Alcohol affects most organs in the body (some researchers indicate that hearing is not affected) and can damage a developing fetus. Intoxication can impair brain function and motor skills; heavy use can increase risk of certain cancers, stroke, and liver disease. Alcoholism or alcohol dependence is a diagnosable disease characterized by a strong craving for alcohol, and/or continued use despite harm or personal injury. Alcohol abuse, which can lead to alcoholism, is a pattern of drinking that result in harm to one’s health, interpersonal relationships, or ability to work.

Alcohol starts affecting the body almost immediately upon consumption with the severity being determined by body size and sex, the type and proof of alcohol, how quickly it is consumed, and what other drugs have been taken with it.  Long term use of alcohol affects almost every organ in the body and can cause serious damage to the liver (cirrhosis).

The short term effects of alcohol include:

        Lowers inhibitions; promotes feeling of no fear;

        Alters perception; slows motor coordination;

        Increases drowsiness and promotes sleepiness;

        Increases heart rate; increases other medical risks due to interaction with mediations;

        Increases risk-taking; reasoning and judgment are often flawed;

        Increases chance of problematic behaviors (The number of people who drink and the way they drink results in harm to self and others including: risky sexual behavior; physical and sexual assaults; potential deleterious effects on the developing brain; problems in school, at work, and with the legal system; various types of injury; car crashes; homicide and suicide; and death from alcohol poisoning).

The long term effects include:

        CNS/Neurological: Alcohol alters brain cells which cause blackouts, memory loss, impaired coordination, and loss of control, slowed reflexes, poor vision and slurred speech.  An intoxicated individual also exhibits poor judgment and often engage in risky behaviors (high risk sexual activities, accidents and aggressive behaviors);

        Heart/Cardio:  Chronic, heavy drinking is related to a variety of heart diseases, including hypertension or high blood pressure, and cardiac arrhythmias or abnormal or irregular heart rhythms.  It also increases the risk of strokes and heart failure;

        Liver Damage: Alcohol takes it greatest toll on the liver which, when healthy, is responsible for several essential body functions.  Liver disease is the leading cause of death in alcoholics.  Alcohol causes an accumulation of excessive fat in the liver which prohibits the liver from functioning properly.  Some common alcohol related liver diseases are:

O        Inflammation of the liver; fatty liver

O        Hepatitis and Cirrhosis of the liver (cirrhosis is scarred or dead tissue; affected portions of liver are permanently damaged

O        Jaundice:  Bile enters the bloodstream when the liver does not functioning properly

O        Alcoholic diabetes: Pancreas ability to produce insulin is effected.

        Stomach/Small intestine/colon: About 20% of consumed alcohol is absorbed into the bloodstreams in the stomach and slightly over 60% in the small intestine.  Excessive alcohol in the stomach can result in excessive hydrochloric acid that can cause deterioration of the stomach lining, hemorrhages, and ulcerations.

         Mouth/bronchi:  Alcohol increases the risk of oral lesions becoming cancerous.  Also increase risk of cancer in the bronchi.

        Circulatory system: Heavy use of alcohol increases risk of high blood pressure, strokes, and arteriosclerosis, (hardening of the arteries), which nay eventually weaken the heart muscle walls.  The heart wont pump enough blood, and this causes breathing difficulties and irregular rhythm (can be fatal).

        Skeletal system: Chronic use of alcohol can result in calcium depletion which can cause brittle bones, fractures, and back pain.   Alcohol may also decrease white blood cells which leaves the body more susceptible to diseases.

        Muscular system:  Chronic use of alcohol increases risk that muscles will lose tone, and appear flabby.

        Kidneys:  Chronic use leads to inflammation and reduced function.

        Reproductive system: Chronic use in males may lead to impotence and in females the ovaries may undergo atrophy.

        Alcoholism and Pregnancy:  Drinking during pregnancy increases the risk of low-birth weight babies and intrauterine growth retardation (increases the risk of infection, feeding difficulties, and long-term developmental problems). Drinking during the first trimester can result in the birth of babies with fetal alcohol syndrome (FAS).  These infants are likely to have irreversible physical and mental abnormalities.  The current recommendation is total abstinence during all phases of pregnancy.



Psychological Effects 

Psychological effects are conditioned by the setting in which the drug is used and the mood of the user.  In general, alcohol affects people psychologically, by first increasing self-confidence and promoting sociability.  It calms and relaxes, sedates and reduces tension.  However, for someone who is already lonely, depressed, or suicidal, the depressant effects of alcohol can deepen these emotions.  For some drinkers alcohol may trigger sociability and talkativeness, for other verbal or physical aggressiveness or violence (often results in spouse abuse and criminal activity).  It has been stated that alcohol releases the innermost emotions within the drinker when intoxicated; some are happy and jovial whereas other are aggressive and violent.  Other psychological effects include impaired judgment, feelings of decreased inhibition, decreases fear, increased risk taking and aggressive humor.  Other (more subtle effects) include delusion, denial, and loss of memory, spontaneous actions, and unpredictable behaviors.

Alcohols psychological effects stem from the drugs interaction with the brains neurotransmitters, particularly serotonin (lack of which causes depression and excess of which causes anxiety), dopamine (which can give a surge of pleasure) and gamma amino butyric acid (GABA).  GABA is the major inhibitory



Withdrawal Syndrome

Withdrawal from chronic, heavy use of alcohol is potentially life-threatening.  The alcoholic should be under the care of a physician during this process. The patient will experience many of the following during the early phase of withdrawal (three to six hours after last drink):

  •         Increase in blood pressure, temperature and heart rate
  •         Nausea and vomiting
  •         Slurred speech; shakes; unsteady gait;
  •         Tremors/shakes; poor coordination
  •         Anxiety
  •         Insomnia
  •         Short attention span



The patient may experience the following during later stages of withdrawal:

  •      Hallucinations (may be distracted, frightened and/or disoriented)
  •      Seizures may occur at any time; may be Grand Mal seizures (a form of    epilepsy marked by severe seizures)
  •     Delirium Tremens (DTs) may develop anytime.  Severe psychomotor activity, extremely agitated state (may act like they are brushing away insects), may be incontinent of urine and stool, uncooperative, confused, talking and having a conversation when no one else is there, diaphoretic, and unaware of where they are.  Once DTs begin they generally last for from 3 to 5 days.  They can be fatal (approximately 20 percent die if no medical help is provided).


After long and heavy use of alcohol, a patient generally needs to undergo detoxification (a process designed to eliminate the alcohol from the patients body).  It is usually provided in a hospital setting lasts for approximately one week.  Medical supervision is strongly recommended during the detoxification to provide medications and in some cases measures to correct water and electrolyte imbalances.  Detoxification may be provided in on outpatient facility but the rate of successful completion is reduced over that in a hospital setting.  Also, patients who need medical care, housing, employment, and transportation are at a high risk of failure to complete the detoxification regime. 

Medications that may be helpful in the treatment of alcohol withdrawal include benzodiazepines and other CNS depressants.  Clonidine may also be helpful to decrease tremors, high heart rate, and hypertension.

Pharmacotherapy for Alcoholism

Medications used during treatment of alcoholism include Disulfiram.  It causes a person to become nausea if they drink while taking the mediation.   Compliance with regular use is difficult in that it is generally taken daily.  Naltrexone has proven effective in reducing the craving for alcohol and researchers have concluded that naltrexone along with adjunct psychotherapeutic approaches (coping skills, relapse prevention, supportive therapy) have proven effective (relapse rates have declined)

 Qs And As (Note: Qs are general and not specifically directed at Depressant drugs)

Q-1: How Do drugs Produce Euphoria?

Drugs change the way the brain works by changing the way nerve cells communicate. Nerve cells, called neurons, send messages to each other by releasing chemicals called neurotransmitters. Neurotransmitters work by attaching to key sites on neurons called receptors. Learn more about how neurotransmitters work in the section How Does Your Brain Communicate?

There are many neurotransmitters, but dopamine is one that is directly affected by most stimulants. Dopamine makes people feel good when they do something they enjoy, like eating a piece of chocolate cake or riding a roller coaster. Stimulants cause a buildup of dopamine in the brain, which can make people who abuse stimulants feel intense pleasure and increased energy. They can also make people feel anxious and paranoid. And with repeated use, stimulants can disrupt the functioning of the brains dopamine system, dampening users ability to feel any pleasure at all. Users may try to compensate by taking more and more of the drug to experience the same pleasure.

Q 2: What Are the Short-Term Effects?

In the short term, some drugs especially stimulants can produce joyful feelings, increase wakefulness, and decreases appetite. Users can become more talkative, energetic, or anxious and irritable. Other short-term effects of stimulants can include increased body temperature, heart rate, and blood pressure; dilated pupils; nausea; blurred vision; muscle spasms; and confusion.  Stimulants can also cause the bodys blood vessels to narrow, constricting the flow of blood, which forces the heart to work harder to pump blood through the body. The heart may work so hard that it temporarily loses its natural rhythm. This is called fibrillation and can be very dangerous because it stops the flow of blood through the body.

Q 3: What Are the Long-Term Effects?

As with many types of drugs, repeated abuse can cause addiction. That means that someone repeatedly seeks out and uses the drug despite its harmful effects. Repeated drug use changes the brain in ways that contribute to the drug craving and continued drug seeking and use that characterizes addiction. Other effects of long-term stimulant abuse can include paranoia, aggressiveness, extreme anorexia, thinking problems, visual and auditory hallucinations, delusions, and severe dental problems.

For example, repeated use of cocaine can lead to tolerance of its euphoric effects, causing the user to take higher doses or to use the drug more frequently (e.g., binge use) to get the same effects. Such use can lead to bizarre, erratic behavior. Some cocaine users experience panic attacks or episodes of full-blown paranoid psychosis, in which the individual loses touch with reality and hears sounds that arent there (auditory hallucinations). Different ways of using cocaine can produce different adverse effects. For example, regularly snorting cocaine can lead to hoarseness, loss of the sense of smell, nosebleeds, and a chronically runny nose. Cocaine taken orally can cause reduced blood flow, leading to bowel problems.

Repeated use of methamphetamine can cause violent behavior, mood disturbances, and psychosis, which can include paranoia, auditory hallucinations, and delusions (e.g., the sensation of insects creeping on the skin. The paranoia can result in homicidal and suicidal thoughts. Methamphetamine can increase a persons sex drive and is linked to risky sexual behaviors and the transmission of infectious diseases, such as HIV. However, research also indicates that long-term methamphetamine use may be associated with decreased sexual function, at least in men.

Q 4: Can These Drugs Be Lethal?

Yes, in rare instances, sudden death can occur on the first use of cocaine or unexpectedly thereafter. And, like most drugs, stimulants can be lethal when taken in large doses or mixed with other substances. Stimulant overdoses can lead to heart problems, strokes, hyperthermia (elevated body temperature), and convulsions, which if not treated immediately can result in death. Abuse of both cocaine and alcohol compounds the danger, increasing the risk of overdose.

Q 5: What Are the Differences Between Cocaine and Methamphetamine?

They act in different ways to increase dopamine in the brain. Cocaine works by blocking the dopamine transporter; that is, it doesnt allow dopamine to be recycled back into the neuron after it has done its work. Methamphetamine interferes with this recycling process as well, but it also causes too much dopamine to be released. Another difference is that cocaine disappears from the brain quickly, while methamphetamine has a much longer duration of action. The longer presence in the brain ultimately makes methamphetamine more harmful to brain cells.

Q 6: If a Pregnant Woman Uses Stimulants, Will the Baby Be Hurt?

In the United States between 2006 and 2007, 22.6 percent (or 20,000) of teens ages 15 to 17 used an illicit drug during their pregnancy. Scientists have found that exposure to cocaine during fetal development may lead to subtle but significant deficits later in life, including problems with attention and information processing abilities that are important for success in school. Research is also underway on the effects of methamphetamine use during pregnancy. So far, the data suggest that it may affect fetal growth and contribute to poor quality of movement in infants.

Research in this area is particularly difficult to interpret because it is often hard to single out drugs specific effects among the multiple factors that can all interact to affect maternal, fetal, and child outcomes. These factors include exposure to all drugs of abuse, including nicotine and alcohol; extent of prenatal care; possible neglect or abuse of the child; exposure to violence in the environment; socioeconomic conditions; maternal nutrition; other health conditions; and exposure to sexually transmitted diseases.

Q 7: What Treatments Are Available for Stimulant Abuse?

Several behavioral therapies are effective in treating addiction to stimulants. These approaches are designed to help the person think differently, change their expectations and behaviors, and increase their skills in coping with various stresses in life. One form that is showing positive results in people addicted to either cocaine or methamphetamine is called contingency management, or motivational incentives (MI). These programs reward patients who refrain from using drugs by offering vouchers or prizes. MI may be particularly useful for helping patients to initially stop taking the drug and for helping them to stay in treatment.

Currently, there are no medications approved by the U.S. Food and Drug Administration to treat people who are addicted to stimulants, although that is an active area of research for NIDA.

As with other drugs of abuse, it is possible for individuals to become dependent upon or addicted too many stimulants. Withdrawal symptoms associated with discontinuing stimulant use include fatigue, depression, and disturbance of sleep patterns. Repeated use of some stimulants over a short period can lead to feelings of hostility or paranoia. Further, taking high doses of a stimulant may result in dangerously high body temperature and an irregular heartbeat. There is also the potential for cardiovascular failure or lethal seizures.

Stimulants should be used in combination with other medications only under a physician’s supervision. Patients also should be aware of the dangers associated with mixing stimulants and OTC cold medicines that contain decongestants; combining these substances may cause blood pressure to become dangerously high or lead to irregular heart rhythms.

Q 8: 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.  The brain communicates via:

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.

Neurotransmitters:  The messages are carried between neurons by chemicals called neurotransmitters.  

Receptors: 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 neurotransmitter.

Transporters: Located on the cell that releases the neurotransmitter, transporters recycle these neurotransmitters (i.e., bringing 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.  

Q 9: How do drugs work in the brain?

Drugs are 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 the network.

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.

Q 10: How do drugs work in the brain to produce pleasure?

All 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 overstimulation 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.

Q 11: 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.

Q 12: Why are drugs more addictive than natural rewards?

When some drugs of abuse are taken, they can release 2 to 10 times the amount of dopamine that natural rewards do. In some cases, this occurs almost immediately (as when drugs are smoked or injected), and the effects can last much longer than those produced by natural rewards. The resulting effects on the brain’s pleasure circuit dwarfs those produced by naturally rewarding behaviors such as eating and sex.16,17 The effect of such a powerful reward strongly motivates people to take drugs again and again. This is why scientists sometimes say that drug abuse is something we learn to do very, very well. 

Q 13: 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 and transmit signals. As a result, dopamine becomes 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 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.

Q 14: How does long-term drug taking affect brain circuits?

We know that the same sort of mechanisms involved in the development of tolerance can eventually lead to profound changes in neurons and brain circuits, with the potential to severely compromise the long-term health of the brain. For example, glutamate is another 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 for this change, which can cause impairment in cognitive function. Similarly, long-term drug abuse can trigger adaptations in habit or non-conscious memory systems. Conditioning is one example of this type of learning, whereby environmental cues become associated with the drug experience and can trigger uncontrollable cravings if the individual is later exposed to these cues, even without the drug itself being available. This learned “reflex” is extremely robust and can emerge even after many years of abstinence.

Q 15:  What other brain changes occur with abuse?

Chronic exposure to drugs of abuse disrupts the way critical brain structures interact to control behavior – behavior specifically related to drug abuse. Just as continued abuse may lead to tolerance or the need for higher drug dosages to produce an effect, it may also lead to addiction, which can drive an abuser to seek out and take drugs compulsively. Drug addiction erodes a person’s self-control and ability to make sound decisions, while sending intense impulses to take drugs.


Various web sites; specifically the NIDA web site