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How does Drug Abuse Affect the Nervous System

How does Drug Abuse Affect the Nervous System

Drug abuse affects the nervous system in a negative way. Scientists say that excessive use of drugs change the chemistry and physiology of the brain. This article will educate you about the effects of drug abuse on the nervous system.
Anuya Waghmare
Did you know
... that rewarding experiences like eating and sex trigger the release of the brain chemical 'dopamine', telling the brain 'do it again'. But when drugs are abused, the brain releases high levels of dopamine (2 to 10 times the amount released normally) that motivates people to take drugs again and again.

Most people are of the notion that it is safe to take prescription and over-the-counter (OTC) drugs, but that's true only when they are taken in the appropriate dose or as prescribed by the doctor. Drug abuse (both legal and illegal) can put the abuser at a risk for various health problems. It can interfere with the normal functioning of the nervous system and damage the important areas of the brain that are responsible for performing specific functions.

Effects of Drugs on the Nervous System

The nervous system consists of two parts, the Central Nervous System (CNS) and the Peripheral Nervous System (PNS). The CNS comprises the brain and spinal cord. The PNS consists of the network of nerves that connect the CNS to the different parts of the body. The brain is the command center of our body and communicates with the rest of the body through the nerves and spinal cord.

The types of drugs that are categorized by their effects on the nervous system are:


If abused, these drugs can interfere with the way neurotransmitters (the chemical messengers that transmit and relay messages between the neurons) send and receive signals. They may block the nerve impulses or prevent the neurotransmitters from binding to specific receptors. Some drugs cause the brain to stop producing its own neurotransmitters or alter the amount of these chemicals in the brain, thus disrupting the normal functioning of the brain. This can destroy neurons and eventually damage the brain and other parts of the nervous system.

Drug abuse affects the psychological, emotional, behavioral, and physical well-being of a person. The effects depend on the age, sex, tolerance levels, amount taken, and for how long.


Stimulants are drugs that excite or stimulate the brain and the nervous system. They speed up the various mental and physical processes in the body, uplift your mood, increase energy, and make you feel more alert. Amphetamines, cocaine, methamphetamines, methylxanthines (e.g. caffeine), and nicotine are examples of drugs that come under this category.

Effects of Stimulants

Stimulants increase the effect of certain neurotransmitters in the body like dopamine and norepinephrine. Dopamine is associated with feelings of pleasure and euphoria, and is called the 'pleasure chemical'. Norepinephrine acts on the areas of the brain that control attention, alertness, and arousal.

Abuse of stimulants is very common. When taken in high doses, they heighten the effect of these neurotransmitters. This interrupts the normal communication between neurons and produces a 'high' or a sense of elation. A desire to get such high spirits causes people to abuse stimulants and get addicted to them.

Dangers of Stimulant Abuse

• High doses of stimulants can result in abnormally high body temperature, irregular heartbeat, and paranoia. It can also increase the risk of seizures, cardiovascular and respiratory problems.

• As mentioned, the effects differ in every individual and depends on the amount taken and how it is taken. In some people, stimulants can lead to panic attacks, confusion, convulsions, and feelings of hostility and aggression.

• Caffeine is a very commonly abused stimulant that affects the central nervous system. Studies say that almost 90% of the world's population regularly consume products containing caffeine. Abuse of caffeine can cause nausea, vomiting, and frequent urination, which can lead to dehydration. In some people, long-term use of caffeine can lead to muscle tremors, restlessness, irritability, stomach irritation, and insomnia.

• Cocaine is another addictive stimulant that affects the brain. It can make the abuser feel energetic and mentally alert. Short-term effects of cocaine include increased temperature, elevated heart rate, and blood pressure. It also affects the gastrointestinal tract causing stomach pain, nausea, and ulcers. Regular use of cocaine could lead to tremors, vertigo, muscle twitches, seizures, and stroke. In extreme cases, it could lead to the death of the user due to cardiac arrest.

• Nicotine, present in tobacco, is another stimulant that affects the nervous system. It compresses the blood vessels, increasing the heart rate and blood pressure. Long-term abuse of tobacco can lead to wrinkled skin, stomach ulcers, a weakened immune system, and also deteriorate the sense of taste and smell. When nicotine enters the brain, it can disrupt the normal functioning of the brain. It also increases the risk of respiratory diseases, heart attacks, stroke, and cancer. According to the World Health Organization, abuse of tobacco causes around 5.4 million deaths globally.

• Avoid taking stimulants with over-the-counter cold and cough medicines, as it can increase your blood pressure or cause irregular heart rhythms. Always consult your doctor before having OTC medicines, as most of them contain more than one active ingredient. Hence, if you take medicines that have the same or similar ingredients, you may end up taking too much of one or more ingredients, which can be harmful.
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Depressants or sedatives are drugs that slow down the brain activity and have a calming effect on the person. They are often prescribed to people who suffer from insomnia, stress and anxiety, seizures, etc. Some depressants are used as general anesthetics as well. Barbiturates, benzodiazepines, sleep medication, alcohol, are some examples of drugs in this category.

Effects of Depressants

Most depressants work on the neurotransmitter GABA (gamma-aminobutyric acid) by increasing its secretion, which slows down the activity of nerve cells in the brain, producing a calming effect. Depressants slow down your reflexes and affect balance and coordination of movements due to muscle relaxation. It makes you drowsy, affects your sense of judgment, and causes confusion and slurred speech.

Dangers of Depressant Abuse

• The dangers of taking depressants include nervousness, anxiety, profuse sweating, nausea, etc. Depressants like barbiturates can cause mild euphoria and relieve anxiety. However, overdose can impair a person's vision, memory, judgment, and motor coordination. In extreme cases it can lead to unconsciousness, coma, and even death.

• Alcohol is a depressant which hinders the signals in the brain and slows down the function of the nervous system. It affects your senses, movement, coordination, and the ability to think clearly. Long-term abuse of alcohol can cause the brain to shrink, leading to the development of serious brain disorders like Wernicke-Korsakoff Syndrome, that causes learning difficulties and memory impairment.

• Consumption of alcohol in large quantities, especially on an empty stomach, can produce a blackout. Drinking too much alcohol, usually over a short period can lead to alcohol poisoning. This affects the areas of the brain that control the functions like breathing and heart rate, leading to unconsciousness, seizures, and even death.

• Alcohol abuse also affects the liver, causing liver cirrhosis. This in turn can lead to hepatic encephalopathy, which damages the working of the brain, causing sleep disturbances, personality changes, mood fluctuations, attention issues, and movement coordination. This can damage the brain cells of the person, increasing the risk for slipping into a coma, or death in extreme cases.

• Benzodiazepines include tranquilizers and sleeping pills, that have serious effects on the central nervous system. They slow down responses such as breathing, heart rate, and brain activity. When taken in high doses with alcohol and barbiturates, they can be particularly dangerous, leading to life-threatening complications, such as coma or death.
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Opiates are drugs that stimulate a pleasure feeling and help in relieving pain. They improve your mood and produce a rush of pleasurable sensation and serenity for a few minutes. Opium, morphine, synthetic painkillers, codeine, heroin, and other narcotic drugs are included in this category.

Effects of Opiates

Our brain secretes natural opiate receptors that control the response of the body to pain. Opiates act on these receptors and block the transmission of pain, which increases the amount of dopamine in the body. Dopamine induces euphoria which relieves stress, discomfort, and creates a relaxed feeling. Opiates affect the capacity of the brain to produce natural opiates, like endorphins. Endorphins are natural painkillers secreted by the brain that alleviate pain and induce a euphoric feeling. This confuses the brain, affecting the working of the brain.

Dangers of Opiate Abuse

• Opiates change the working of the brain's limbic system. They can alter the brain and affect your emotions. Opiates can also cause constipation, drowsiness, reduce the heart rate, widen the blood vessels, and lower a person's coughing and breathing reflexes.

• Heroin is the most commonly abused opiate. The effects include, nausea, dry mouth, slurred speech, and inability to coordinate movements. Long-term use of heroin affects the nerve cells and causes permanent damage to the transmission of signals between the neurons. It hampers your ability to think, judge, and grasp situations. It also affects the natural production of endorphins, which causes chemical imbalance in the brain, that can affect your mood, emotions, and overall well-being.

• Opiates, when combined with depressants like alcohol or sleep medication, can have life-threatening consequences due to change in the breathing rate. In fact, an overdose could cause severe breathing complications, leading to coma, or even death.
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Hallucinogens or psychedelic drugs are drugs that act on the central nervous system, producing changes to the user's perception and state of mind. They have physical and psychological effects on the body. Lysergic acid diethylamide (LSD), ketamine, phencyclidine (PCP) are some of the drugs that come under hallucinogens.

Effects of Hallucinogens

Hallucinogens affect the brain by altering the interpretations of sensory input. These drugs cause hallucinations, disturb the sense of color and perception, affect cognitive ability, and create a state resembling delirium. Some hallucinogens may destroy the neurons that produce serotonin, which stabilizes our mood. Serotonin also plays an important role in other body functions like controlling hunger, muscle movements, regulating body temperature, etc. Hallucinogens impair a person's ability to perceive, think, understand, and make sensible decisions and judgment. Long-term effects include severe depression, resulting in suicidal tendencies or death.

Dangers of Hallucinogen Abuse

• The use of hallucinogens can cause dilated pupils, elevated body temperature, loss of appetite, increased heart rate and blood pressure, tremors, headache, palpitations, and blurry vision.

• Hallucinogens alter the brain by producing illusions and hallucinations. Your ability to think and awareness about self is altered. Paranoia, emotional instability, hot flashes, mood changes, and aggressive behavior are the common effects of hallucinogens. Flashbacks can occur in some people which can last for days, months, and sometimes even years. It can also lead to depression, as over time a person gets used to these hallucinogens, and he may find it hard to distinguish between reality and hallucinations.

• LSD is a well-known hallucinogenic drug that causes hallucinations. It affects the brain's limbic system, causing intense emotions and visual delusions. The other adverse effects of LSD include, excessive sweating, dry mouth, increased blood pressure, body temperature and heart rate, sleep deprivation, tremors, etc.
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Points to Remember

❖ Drugs that increase blood pressure, change your perception, and affect the function of the brain can cause potentially serious complications.

❖ Tolerance to drugs develop when the brain adjusts to a certain dose of a drug. Due to this, you may feel the need to take the drug in larger amounts to feel its effect. Overdose of drugs can lead to death in extreme cases.

❖ Substance abuse can also lead to mental health problems like depression, anxiety, bipolar disorder (mood changes), ADHD (attention deficit hyperactivity disorder), or antisocial personality disorder.

❖ Drug addiction is a chronic disease, hence, the treatment is not simple. Along with medication, motivational and behavioral therapies, a person needs tremendous will power, patience, support, and understanding from loved ones to come out of it.

Drug abuse disrupts many facets of an individual's life. It adversely affects the individuality of a person and changes his physical, mental, social, and emotional state. So stay away from this poison and be safe!

Disclaimer: This WellnessKeen article is for informative purposes only and should not be used as a replacement for professional medical advice.