Drugs and Disorders of the Nervous System

What is a drug?

Any chemical substance that comes from outside the body and alters or modifies the chemical reactions in the body.

Types of drug

To treat an illness or disorder, medicine is used and all of them contain drugs, like aspirin tablets, contain the drug “acetylsalicylic acid,” but not all drugs are medicines. Antibiotics are drugs which are used for the treatment of bacterial diseases. Alcohol and nicotine are drugs but are not usually considered as medicines.

Different parts of the body were affected by various drugs. Some drugs act directly on the nervous system and are often grouped according to the effect they have, for example:


They speed up the action of the nervous system and usually make the drug user feel confident and alert, and include “amphetamines,” “caffeine” and “nicotine.”


The action of some parts of the nervous system was slowed down by the use of depressants. The user feels sleepy and unconscious but may become dependent on the drug-like, “barbiturates,” “alcohol” and “cannabis.”


They act like depressants but particularly target the brain. Narcotics work as pain-killers and results in the feeling of drowsy well-being or euphoria. Heroin is one of the narcotics and is likely to bring drug dependence in the user.


Analgesics are mild pain-killers, for example, aspirin and paracetamol (widely used).

Social drugs may be abused

Social (recreational) drug is taken for non-medical reasons.

Examples include:

  1. Legal drugs, such as nicotine in cigarette smoke
  2. Alcohol
  3. Illegal drugs, such as amphetamines and LSD

These drugs are taken for pleasurable sensations that they give the user. Users may become dependent on the drugs because they are unwilling to give up those pleasurable sensations. This psychological and emotional addiction may then be followed by a physical addiction.

The person becomes physically addicted to the drug and if he/she cannot get the drug, will then receive the “withdrawal symptoms” that occurs after some hours without the use of drugs:

  1. vomiting
  2. trembling
  3. sweating profusely
  4. severe abdominal pain
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The dangers of abusing social drugs

Many casual users of social drugs soon become dependent upon them (physically and psychologically), so the drug becomes a dominant feature of everyday life. To satisfy the desire for the effects of the drug, the user will do almost anything and this lead to problems such as:

  • Malnourishment — drug depresses the hunger
  • Financial problems — drugs can be expensive and addicted ones start to stealing
  • Infection — needles led to infection by injecting drugs, including HIV and hepatitis

The drugs may also lead to dangerous behaviour such as poorly coordinated driving after drinking alcohol or erratic behaviour when using a hallucinogen.

Effects of the drug on the central and peripheral nervous system

The brain is affected by several drugs:

  1. Heroin — mimics the action of the body’s natural pain-killers. This gives a pleasurable sense of well-being.
  2. Alcohol — can upset normal sleep patterns by reducing the levels of ‘calming agents’ in the brain.

Many drugs have their effects at synapses (transfer nerve impulses as chemicals called neurotransmitters). Drugs also have their effects by changing the concentration of neurotransmitters, or by mimicking what they do.


Alcohol affects the emotional centres in the forebrain and acts as a depressant. It overrules normal social restraints and at low concentration, alcohol, therefore ‘lifts’ social inhibitions.

At high concentrations, the life-support centres in the medulla are depressed. As a result, breathing may stop, causing brain damage or even death.

In peripheral nerves, alcohol slows down impulses causing slower reactions. It also affects nerves that control blood flow to the skin, causing its flushing.


Nicotine in tobacco smoke is a stimulant which mimics the natural neurotransmitters in the part of the nervous system concerned with the control of heartbeat and blood pressure.

Alcohol is the most widely used drug

Alcohol is widely available legally in many countries and is an unusual drug. Even youngsters that cannot buy alcohol legally may still be able to obtain it quite easily. Apart from some cultures which ban alcohol, very few people have never tried the drug and most young people would not consider it as a ‘drug of abuse’.

However, alcohol is an addictive drug and causes great damage when used in excess and many people underestimate the quantity of alcohol they intake.

The effects of alcohol on body extend beyond the nervous system as listed below:

  1. Cardiovascular effects cover anaemia (alcohol poisons bone marrow) and fats are deposited in the coronary arteries.
  2. Warmblood flows to the skin as its blood vessels dilate. The body feels warm and comfortable, but hypothermia may result in low environmental temperatures.
  3. Alcohol’s 1 unit is the amount that can be processed by the liver in 1 hour in the average person. This is identically tantamount to one glass of wine, half a pint of potation, or one measure of spirits.
  4. Liver cells work harder to detoxify the alcohol. Cells lining blood vessels are damaged causing cirrhosis — liver functions began to fail.
  5. Kidneys cannot reabsorb water which led to the excretion of too much water and the body becomes dehydrated (this is responsible for the headache following a drinking bout).
  6. Sex organs do not work well as in males, sperm count may be reduced.
  7. Drugs irritate the intestines, cause indigestion, nausea, diarrhoea and ulcers.
  8. In pregnant women, alcohol crosses the placenta to the fetus. As a result, the child develops slowly, especially its nervous system and this is called fetal alcohol syndrome.
  9. Tongue and oesophagus cancers are possible in heavy drinkers.
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Disorders of the nervous system

Many drugs have their effect by altering the activity of the nervous system and is also be harmed by medical conditions.

  1. Drugs more likely show their effects in old age (such as Alzheimer’s disease)
  2. Some strike at any time (such as multiple sclerosis)
  3. Caused by infection (such as meningitis)
  4. Some may result from an injury (such as a broken back)

These problems may cause great hardship to the affected person, and to those who care for them.

As seen on:

  1. https://interact.pk/drugs-and-disorders-of-the-nervous-system
  2. https://medium.com/@HamnaQasim/drugs-and-disorders-of-the-nervous-system-6d93c8ea60e7
  3. https://issuu.com/home/published/drugs_and_disorders_of_the_nervous_system.docx
  4. https://medium.com/@HamnaQasim/drugs-and-disorders-of-the-nervous-system-6d93c8ea60e7