The Commonly Abused Drugs

Surveys show that the use of drugs and alcohol has been rising, especially among the young, and this is a real cause for concern. The drugs most commonly abused fall into three groups — opioids, cannabinoids and coca alkaloids. Most of these come from flowering plants, and a few from fungi.

What ties them together is not their chemistry but the way they are misused. Each acts on the nervous system, and each is taken not for medical reasons but for the feelings it produces — which is exactly where the trouble begins.

Opioids — Heroin and Morphine

Opioids bind to specific opioid receptors present in the central nervous system and the gastrointestinal tract.

The best-known example is heroin, commonly called smack. Chemically it is diacetylmorphine, a white, odourless, bitter, crystalline compound. It is obtained by the acetylation of morphine, which in turn is extracted from the latex of the poppy plant Papaver somniferum. Heroin is generally taken by snorting or injection. It is a depressant, meaning it slows down body functions.

Morphine itself is not only a drug of abuse — it is a very effective sedative and painkiller, especially useful in patients who have undergone surgery.

Cannabinoids — Cannabis Sativa

Cannabinoids are a group of chemicals that interact with cannabinoid receptors located principally in the brain.

Natural cannabinoids are obtained from the inflorescences of the plant Cannabis sativa. The flower tops, leaves and resin of the cannabis plant are used in various combinations to produce marijuana, hashish, charas and ganja. They are generally taken by inhalation or oral ingestion, and are known for their effects on the cardiovascular system of the body. In recent years cannabinoids have also been abused by some sportspersons.

Coca Alkaloid — Cocaine

The coca alkaloid, or cocaine, is obtained from the coca plant Erythroxylum coca, native to South America.

Cocaine interferes with the transport of the neurotransmitter dopamine. Commonly called coke or crack, it is usually snorted. It has a potent stimulating action on the central nervous system, producing a sense of euphoria and increased energy; an excessive dose causes hallucinations.

Other well-known plants with hallucinogenic properties are Atropa belladonna and Datura.

Medicines That Get Misused, and What Counts as Abuse

Some drugs meant to heal are also abused. Barbiturates, amphetamines, benzodiazepines and similar drugs are normally used as medicines to help patients cope with mental illnesses such as depression and insomnia, yet they are often misused. Morphine, as noted, is a valuable sedative and painkiller after surgery.

Several plants, fruits and seeds with hallucinogenic properties have been used for hundreds of years in folk medicine and in religious ceremonies and rituals across the world. The line is drawn by purpose and amount: when any of these substances is taken for a reason other than medicinal use, or in amounts or at a frequency that impairs one's physical, physiological or psychological functions, it constitutes drug abuse.

Quick Recap

  • The commonly abused drugs are opioids, cannabinoids and coca alkaloids, mostly from flowering plants (some from fungi).
  • Opioids bind opioid receptors in the CNS and gut; heroin (smack) is diacetylmorphine, made by acetylation of morphine from the latex of Papaver somniferum; a depressant, taken by snorting or injection.
  • Cannabinoids act on cannabinoid receptors in the brain; from the inflorescences of Cannabis sativa → marijuana, hashish, charas, ganja; taken by inhalation or orally; affect the cardiovascular system.
  • Cocaine (coke/crack) from Erythroxylum coca interferes with dopamine transport; a potent CNS stimulant giving euphoria; excess causes hallucinations. Other hallucinogenic plants: Atropa belladonna and Datura.
  • Barbiturates, amphetamines and benzodiazepines (medicines for depression/insomnia) are also abused. Using any of these non-medically or in harmful amounts is drug abuse.

Solved Examples — Section 11

Q1. Name the three groups of commonly abused drugs and their usual source.

Answer: The three groups are opioids, cannabinoids and coca alkaloids. The majority are obtained from flowering plants, and some are obtained from fungi.

Q2. What is heroin chemically, and how is it obtained?

Answer: Heroin (smack) is chemically diacetylmorphine, a white, odourless, bitter crystalline compound. It is obtained by the acetylation of morphine, which is extracted from the latex of the poppy plant Papaver somniferum.

Q3. From which plant are natural cannabinoids obtained, and what products are made from it?

Answer: Natural cannabinoids come from the inflorescences of Cannabis sativa. Its flower tops, leaves and resin are used in various combinations to produce marijuana, hashish, charas and ganja.

Q4. How does cocaine act, and what neurotransmitter does it affect?

Answer: Cocaine is obtained from Erythroxylum coca and interferes with the transport of the neurotransmitter dopamine. It is a potent CNS stimulant producing euphoria and increased energy, and an excessive dose causes hallucinations.

Q5. Name two plants, other than cannabis and coca, that have hallucinogenic properties.

Answer: Atropa belladonna and Datura are two well-known plants with hallucinogenic properties.

Q6. When does the use of a drug become drug abuse?

Answer: When a drug is taken for a purpose other than medicinal use, or in amounts or at a frequency that impairs one's physical, physiological or psychological functions, it constitutes drug abuse.