5 most addictive substances and their effects on our brains

2024 Author: Malcolm Clapton | [email protected]. Last modified: 2023-12-17 03:44

About what some drugs, alcohol and nicotine do to our body.

This rating was compiled by the British psychiatrist, professor of neuropsychopharmacology David Nutt and his research team.

1. Heroin

Heroin is an opioid drug, the use of which develops a strong mental and physical dependence. This is due to the fact that when injected, the substance quickly enters the brain, easily overcoming the blood-brain barrier between the circulatory and central nervous systems. In the brain, it causes an increased production of dopamine. Experiments on experimental animals have shown an increase in the level of this pleasure hormone by 200%.

Heroin mimics natural substances in the brain that were created by nature to control pain and increase pleasure.

An additional mechanism of addiction is the increased production of the excitatory neurotransmitter glutamate. Combined with severe withdrawal symptoms - pain, anxiety, seizures, insomnia - this leads to extreme addiction. The breakdown begins 4-24 hours after the last dose, and the addict is in dire need of another portion of the drug. In addition, the body quickly develops a tolerance to heroin - each time a person needs more and more doses.

Heroin addicts often die from heart attacks, strokes, as the drug affects the state of the cardiovascular system. Another cause of death is exhaustion, which leads to constant stimulation of the central nervous system. Experts gave this drug three points out of three possible in terms of the degree of addiction formation.

2. Cocaine

Cocaine is an alkaloid found in plants of the genus Erythroxylum. In nature, it acts as an insecticide and protects the leaves of shrubs from being eaten by insects. Cocaine has a powerful stimulating effect on the central nervous system, causing a feeling of euphoria.

Usually, the brain's reward system works according to certain rules. A neurotransmitter - in this case dopamine - travels to a space between neurons called a synapse. Specialized receptors transmit a signal to respond to its appearance, then remove the neurotransmitter from the synapse to stop its action.

Cocaine blocks dopamine reuptake systems, forcing it to work over and over again, leading to a blast of pleasure.

However, the cocaine euphoria does not last forever, and after the end of the drug's effect, a phase of the suppressed state sets in. Other side effects include fatigue, anxiety, and insomnia.

Cocaine is harmful to the cardiovascular system. It causes powerful spasms that can lead to cerebral hemorrhage, disrupt the work of the heart or other organs. Another negative effect is a state of acute psychosis in which a person has little control over himself. In addition, there is a myth that cocaine is not addictive, but it is not.

3. Nicotine

Nicotine, like cocaine, is an alkaloid that naturally carries out the function of fighting insects. It is the main constituent of tobacco that is addictive. Nicotine is rapidly absorbed by the lungs and transported to the brain. It increases the activity of nicotinic acetylcholine receptors, which leads to the release of adrenaline. This temporarily stimulates various systems of the body, and the person feels more cheerful and active. And the release of dopamine accompanies smoking with a feeling of pleasure.

Nicotine is toxic, long-term use contributes to the development of cancer, ischemia, angina pectoris, and so on. WHO claims that up to 50% of smokers die from addiction-related causes.

4. Barbiturates

Sedatives and hypnotics based on barbituric acid have a depressing effect on the central nervous system. Depending on the dosage, medications can be mildly relaxing or lead to coma.

Barbiturates stimulate the receptors of the inhibitory neurotransmitter - gamma-aminobutyric acid, as a result of which the transmission of impulses to the central nervous system slows down. This leads to muscle relaxation, calming, and eliminates anxiety. The problem of drug dependence was hushed up for a long time, but later they recognized and abandoned barbiturates in favor of benzodiazepines.

Moreover, if cocaine and heroin are illegal, then these drugs have been relatively available for a long time, which increases their danger.

5. Alcohol

Alcoholic beverages, absolutely legal in most countries, are named the most dangerous drug in the world. They also cause addiction quickly enough. Animal studies have shown that alcohol increases dopamine levels by 40–360%.

Alcohol enhances the effect of gamma-aminobutyric acid (GABA), the main inhibitory mediator of the nervous system. Therefore, the movements and speech of drunk people slow down, and the dose of alcohol relaxes. GABA gradually adapts to changes by decreasing the activity of the corresponding receptors, which makes the brain addicted to alcohol.

If a person stops drinking alcohol, the decreased activity of GABA receptors leads to a weakening of the function of nerve inhibition, and the brain becomes more excitable.

At the same time, ethanol reduces the ability of another neurotransmitter, glutamate, to affect NMDA receptors. With long-term alcohol consumption, the number of these receptors increases. The brain becomes less sensitive to alcohol and more sensitive to glutamate. This increases excitability, leading to withdrawal symptoms: seizures, anxiety.

Another reason for the formation of addiction is the ability to quickly receive energy to nourish the brain. This requires acetate, an intermediate product of ethanol metabolism. The brain is hooked on a simple energy source. In the body of a regularly drinking person, alcohol replaces the usual source of energy - glucose.

According to the WHO, every year in the world due to alcohol use 3, 3 million people die. The statistics include diseases and injuries associated with drunkenness.

Dr. Nutt himself noted that the legal status of a drug is not necessarily related to addiction or harm from it. Tobacco and alcohol occupy high positions in the ranking, but remain legal.

However, the existence of this list does not mean at all that the substances that did not get into it do not cause addiction. Therefore, the rating should not be perceived as a tool for dividing drugs into harmful and harmless. The use of any psychoactive substance has consequences.