Drugs and Their Effects on Human Body

Drugs and Their Effects on Human BodyDrugs. A word that is loved and hated at the same time. Both cursed and honoured. They can do both: help and destroy. The word originated from the Dutch word "droog" meaning "dry". Later, this word started to be used for psychoactive substances. The word drug also figuratively describes very popular situations or directly addictions, sch as sexual intercourse or gambling.

Similarly as in other languages, the word drug has several meanings in Czech language. The first one interprets drugs as medicines. Their application focuses on help in health problems and deficiencies. This group includes dried or otherwise processed and conserved plants, animal parts or products of their metabolism. The shift in the meaning of the word drug probably happened from vegetable drugs with psychoactive effects to the contemporary interpretation of addictive substances (psychoactive substances). They are the main subject of this article. They are chemical substances primarily affecting the nervous system where they alter brain functions and cause temporary changes in perception, mood, consciousness and behaviour. These substances are usually illegal or limited by the government. People use drugs for many various reasons and that makes drugs present in all social strata. The methods of use also vary and help us classify drugs into several sub-groups:


Anaesthetics are substances that cause partial or complete loss of sensation. Many anaesthetics can even induce unconsciousness, allowing a medical procedure to be performed without physical pain or emotional trauma for the patient. These include e.g. ether, ketamine and some barbiturates.


Analgesics are substances from the extensive group of medicinal drugs used for pain relief or for achieving analgesia (i.e. a painless state). They include opioids such as morphine and codeine and non-steroid anti-inflammatory agents such as aspirin and ibuprofen..

Drugs and Their Effects on Human Body


Psychiatric drugs aim to inhibit mental and emotional disorders. There are 6 main groups in total. 

  • Antidepressants are used to treat disorders such as clinical depression or dysthymia. For example fluoxetin (Prozac).
  • Psychostimulants used to treat hyperactivity or narcolepsy. They include e.g. metamphetamine, cocaine, caffeine or nicotine.
  • Antipsychotics for psychoses, schizophrenia and manias.
  • Mood stabilisers used for bipolar and schizoaffective disorders. For example lithium.
  • Anxiolytics used for anxiety disorders.
  • Depressants used as hypnotics, sedatives and anaesthetics. 

Recreational Drug Use or I Am Not Addicted, I Just Wanna Have Fun! 

According to a survey from many countries of the European Union, recreational drug use is usually a part of a new so-called consumerist life style and it is usually limited to a specific period in the life of youth until family and work obligations come. At the same time, there are "hardcore" recreational users. They use a lot. They are the ones who "enjoy their life to the fullest".

Thanks to use of stimulating drugs that make people last active longer, there was a boom of entertainment in night clubs. Easy availability of drugs in this environment is the decisive factor. The relationship between nightlife, music and recreational drug use is nothing new. Avantgarde jazz musicians used to use marijuana and cocaine recreationally already in the 1930s. The rock scene of the 1960s and the punk scene of the 1970s extended the list of drugs used by amphetamines, hallucinogens and many medicinal drugs with psychotropic effects. In the 1980s, some parts of Europe saw the arrival of MDMA or "ecstasy" which was used in the environment of electronic dance scene. Ten years later, ecstasy and dance music have spread around the world. That is why it is no wonder that the use of synthetic drugs raised a wave of international interest in seeking appropriate measures. 

Soft or Hard Drugs?

Psychoactive drugs are sometimes divided into soft and hard drugs. This classification is supposed to express the extent of danger these drugs to their users. There are drugs with acceptable risks and drugs where the risk related to their use is too serious and therefore unacceptable. 

The category of soft drugs usually includes marijuana, hashish, caffeine and theine, sometimes also psychedelic substances such as LSD or peyote, but mainly psilocybine fungi. MDMA (ecstasy) is on the edge, sometimes described as a soft drug. Alcohol toxicity and addictiveness (and therefore social danger) are higher than MDMA toxicity and addictiveness.

Doctors consider alcohol a hard drug and only its legality in most states raises doubts about its classification. Alcohol induces physical addiction; it has fatal abstinence syndrome and directly damages cells. Hard drugs also include metamphetamine, cocaine, toluene and opioids


Another type of classification which is used more frequently is classification according to the drugs' effects. This system considers the prevailing effect of the substance on mental state of healthy people. That means that if the substance is classified as a hallucinogen, it doesn't mean it has no stimulating effect as well.


Drugs and Their Effects on Human BodyCannabinoids are hallucinogenic substances contained in the Cannabis plant (hemp). Cannabis contains many active substances, but from our perspective the most interesting one is delta-9-tetrahydrocannabinol (THC), the bearer of hallucinogenic effects. Cannabinoids also include marijuana and hashish.

  • Hashish is actually the very resin acquired from hemp and contains up to 40% of active substances.
  • Marijuana is a blend of hemp leaves, twigs, seeds, blossoms and cobs. Marijuana and hashish are considered soft drugs and many people think that using them is safe. However, this opinion is not entirely true. Although serious complications are fairly rare, long-term use leads to rather typical memory, concentration and learning disorders and to loss of motivation. In men, long-term marijuana use reduces potency. The opinion that these drugs are not addictive is also wrong; research has shown that they cause both mental and physical addiction.

Hallucinogens (Psychedelic Substances)

Hallucinogens influence human consciousness significantly and they cause mental changes that can lead even to the stage of toxic psychosis. This group includes a large amount of substances frequently used in medicine; the notorious ones are LSD and ecstasy. In Czech environment, it is mainly psylocibine.


  • LSD exists almost exclusively in the form of so-called trips or crystals. Using LSD is very dangerous mainly because its effects are unforeseeable and in some cases, even the first use may bring problems such as hallucinations and panic reactions that can last for as long as several days.
  • Psilocybine is a strong psychoactive substance and it occurs in Psilocybe mushrooms. This drug is the most frequent hallucinogenic drugs in the Czech Republic.
  • Chemically, ecstasy is a phenethylamine and it is on the edge of hallucinogenic drugs and stimulants.  After using the drug, the affected persons usually shows feelings of calmness and comfort; stress blows away and mood brightens, there are feelings of empathy and the need to touch someone. However, side effects of using this drug are very dangerous as they include absence of thirst which may lead to overheating. Another dangerous side effect is damage to neurons.



The name of this group stems from the word opium which is a substance contained in unripe poppy-heads. Opiates are substances with chemical structure similar to morphine which is the active substance in most opiates. Their effects make opiates very useful in medicine (narcotics). Opiates and volatile substances are considered the most dangerous psychoactive drugs because their addiction potential is very high. Main opiates include opium, heroin, morphine, oxycontin and subutex.

Drugs and Their Effects on Human Body


Originally, they were medicinal drugs for treating psychotic conditions; they rid the patients of fear and hallucinations, they relax and calm them and reduce their aggression. However, they are often abused. They have a wide range of side effects - they may cause coordination disorders, induce a condition similar to Parkinson's disease, circulatory system and memory disorders and worsened sexual functions. They are dangerous as they are able to cause strong mental and physical addiction with abstinence symptoms including epileptic paroxysmal attacks. The most frequently abused tranquilizers include barbiturates, benzodiazepines and rohypnol.


Stimulants are psychoactive drugs that improve mental and physical functions; their chemical compositions vary greatly. Stimulants render physical and mental enhancement that can take forms ranging from a light feeling of freshness to uncontrollable excitement.

The most significant representatives of illegal-drugs group are metamphetamine, cocaine and amphetamines; legal stimulants are substances with lower effects - coffee and tea. Although stimulants do not induce physical addiction, they do cause very strong mental addiction. Using stimulants increases the risk of cardiac and brain disorders.

Volatile Substances

Volatile substances are the most dangerous group, even more dangerous than drugs as cocaine, metamphetamine or heroin. They manifest with strong narcotic (inhibiting) effects and it is very easy to get overdosed fatally. Their use causes severe and irreversible damage to the brain, kidneys, liver and bone marrow. They are hydrocarbons and they are most frequently represented by toluene.

The aforementioned information led us to a fairly uncomplicated system of classification of addictive substances. However, the topic of drugs is incredibly wide and almost inexhaustible. How do drugs influence our lives and the society? How do we recognize the presence of drugs in our surroundings? And what can we do? This and much more is waiting in Part 2 of this Article.

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