THE 6 TYPES OF DRUGS AND THEIR EFFECTS ON THE BRAIN AND BEHAVIOR - ARTE - 2025

There are five types of drugs according to their active principles, with different effects: cannabis, opiates, stimulants, legal (nicotine and alcohol) and designer drugs. There is really a very fine line that separates drugs from drugs of abuse since many drugs have active ingredients and effects similar to recreational drugs if they are taken repeatedly and abundantly.

Therefore what really separates these drugs is the dose that the user takes. For example, barbiturates are a type of drug used to alleviate anxiety but in high doses it can be used as a hypnotic and sedative drug.

Drugs / drugs under international control include amphetamine-type stimulants, cocaine, cannabis, hallucinogens, opiates, and sedative-hypnotics. Most countries have decided to restrict their use because they can be harmful to health.

Although some of the physical effects of drugs may sound pleasant, they do not last long and can lead to dependence.

Although here in this article we have made a classification according to the active principles, they can also be classified according to whether they are legal drugs or illegal drugs.

The 6 main classes of drugs according to the active principles

Cannabis

The cannabis or marijuana usually take grinding dried leaves and fumándoselo, but also consume their usual pressed resin or hashish, usual mixed with snuff. Its active principle is THC (delta-9-tetrahydrocarbocannabinol). THC binds to the CB1 receptors of the cannabinoid system.

It is curious that in our body there is a cannabinoid system, which indicates that we have endogenous cannabinoids, that is, natural cannabinoids secreted by our own body (for example anandamide).

In addition, the number of cannabinoid receptors in our central nervous system is greater than that of any other neurotransmitter, in certain areas of the brain their number is up to 12 times greater than that of dopamine receptors.

The cannabinoid system acts primarily in the cerebellum, which governs motor coordination; in the brain stem that regulates vital functions; and in the striatum, the hippocampus and the amygdala, responsible respectively for reflex movements, memory and anxiety.

Brain effects

Taking cannabis releases cannabinoids that interact with cannabinoid receptors that in turn trigger the release of dopamine from the reward system, specifically the nucleus accumbens.

This increase in dopamine creates a pleasant effect that works as a booster and makes the person who consumes it feel like continuing to take it. Therefore, the type of dependency it causes is psychological.

Behavioral effects

Its main behavioral effects at low doses are, euphoria, reduction of certain pain (for example eye), decreased anxiety, sensitivity to colors and accentuated sounds, decreased short-term memory (recent memories), movements are slowed, stimulation of appetite and thirst and loss of consciousness of time.

At high doses it can induce panic, toxic delirium and psychosis.

All these effects are transitory, their duration depends on the sensitivity of each person and the amount taken, but they do not usually last more than an hour.

In chronic heavy users it can have long-term effects such as decreased motivation and social decline.

Data of interest

Does it cause dependency?

As indicated above, cannabis does not cause long-term neuronal changes and acts on the reward system, which is why it does not cause physical dependence but it does cause psychological dependence.

Does it cause tolerance?

Indeed, regular marijuana users feel like the same amount of drug has less and less effect on them and they must consume more to feel the same.

Does it cause withdrawal syndrome?

Recent studies with mice chronically exposed to THC have found that they suffer from withdrawal. It is not yet known whether it also occurs in humans, although it is very likely.

Can it cause schizophrenia?

In a recent study by Dr. Kuei Tseng, it was found that the repeated supply of THC to rats during adolescence caused a deficit in the maturation of the GABAergic connections of the ventral hippocampus with the prefrontal cortex, which would cause a decrease in control of impulses. This effect did not occur when cannabis was administered to adult rats.

In patients with schizophrenia it has been proven that this maturation deficit exists, but to develop schizophrenia it is necessary to have a genetic predisposition and live in a certain environment.

Therefore, the mere fact of consuming marijuana during adolescence cannot cause schizophrenia, but it can induce it in people with a genetic predisposition and increase the chances of suffering it.

Can it be used as a therapeutic agent?

Cannabis has therapeutic properties such as anxiolytic, sedative, relaxing, analgesic and antidepressant. It is recommended in low doses for numerous diseases that cause pain such as multiple sclerosis.

If you want to know more about this type of drug, I recommend the following video:

Opiates

The opioids are substances derived resin or poppy plant opium. It can be ingested almost in any way, it can be eaten, smoked, injected…

The most common opiate is heroin, which is usually administered intravenously, this type of administration is especially dangerous because the necessary hygienic measures are not usually followed and diseases can be spread.

As with cannabis, there are endogenous opiates, the most important of which are opioid peptides, the so-called “brain morphines”. These opiates bind to opioid receptors, the most important of which are the mu (µ), delta (∂), and kappa (k) type.

Endogenous opiates such as endorphins and enkephalins are stored in opiate neurons and are released during neurotransmission and act on the reward system to mediate reinforcement and the feeling of pleasure.

Brain effects

Opioids act on GABA, a neurotransmitter in the brain's inhibitory system, which slows down neurons and slows down the transmission of other neurotransmitters.

By blocking the function of GABA nucleus accumbens (structure of the reward system), the reuptake of dopamine that has already been released is prevented, making our body believe that there is not enough dopamine, so a torrent of this neurotransmitter is discharged, which will cause the sensation of pleasure.

Behavioral effects

The effects of opioids can range from calming to analgesia (both physical and psychological). Although a chronic intake can lead to complete desensitization to both endogenous and exogenous stimuli.

At high doses it produces euphoria, which is its main reinforcing property, followed by a deep sense of tranquility, drowsiness, affective lability, mental clouding, apathy and motor slowness.

These effects can last for several hours. If an overdose is suffered, it can depress the respiratory system, leading to coma.

Data of interest

Does it cause dependency?

Indeed, the chronic administration of opiates causes both physical and psychological dependence, since it modifies opioid receptors and affects the reward system.

So people dependent on this substance continue to consume it both for the pleasant effects and for the adverse effects of not taking it.

Does it cause tolerance?

The answer is yes, and tolerance begins quite quickly, it does not take a long time to take this drug to feel it, since opioid receptors adapt quite quickly.

As explained before, tolerance implies that the individual must take more amounts of the drug each time to feel its effects, so in the long run the dose necessary to feel euphoria can lead to overdose.

Does it cause withdrawal syndrome?

Chronic administration of opioids modifies the receptors making them adapt and less sensitive, so that stimuli that were previously pleasant are no longer pleasant. The main symptoms of the withdrawal syndrome are dysphoria, irritability, and autonomic hyperactivity characterized by tachycardia, tremors, and sweating.

Can it be used as a therapeutic agent?

Yes, and in fact it is used, morphine is a type of opioid that in low doses causes sedation but in high doses it can cause coma and even death. Its chronic administration causes dependence, tolerance and withdrawal, as occurs with other opioid substances.

If you want to know more about this type of drug, I recommend the following video:

Stimulants: cocaine and amphetamine

The main stimulant drugs are cocaine and amphetamine and their derivatives such as "crack" or methamphetamine.

Cocaine is extracted from the coca leaf, formerly it was burned and consumed directly, but today its preparation is much more complex, firstly the coca leaf is stepped on until all the sage comes out, to that "broth" They add lime (hence cocaine is a white powder), sulfuric acid, and kerosene which serve as fixatives and increase the effects of cocaine on the brain.

As can be seen, the "ingredient list" of cocaine is not healthy at all, its compounds are highly toxic and can be more harmful than cocaine itself.

In addition, it is usually snorted, which is highly dangerous because it makes the drug reach the brain as soon as possible through the blood vessels of the nose, this procedure causes great physical damage because it wears the nasal septum.

Currently in some indigenous peoples of South America the coca leaf continues to be consumed, they chew it for energy and to alleviate the so-called "altitude sickness".

The crack, or base, is a derivative of cocaine sold in the form of stone. It can be snorted, injected or smoked. Its effect is more intense than that of cocaine as it takes less time to metabolize.

The amphetamine is a type of synthetic drug sold in tablet and is usually administered orally to the like methamphetamine.

Due to its mode of administration, it tends to have less intense effects than cocaine and its derivatives. Its way of making it is complex and you need to know chemistry to be able to do it, as we have been shown in Breaking Bad.

Brain effects

Both cocaine and amphetamine act by blocking the dopamine transporter (DAT), in this way dopamine remains free and is concentrated in key areas such as the nucleus accumbens, an area of ​​the reinforcement system.

Amphetamine, in addition to blocking the dopamine transporter, blocks the receptors so dopamine cannot be re-uploaded and continues to produce and concentrate more and more until it is depleted. Dopamine can stay active up to 300 times longer than it is normally activated.

Dopamine is one of the most important neurotransmitters in the brain, the effects that stimulant drugs have on dopamine affect areas involved in motivation (limbic area) and the control of our actions (prefrontal cortex) and also certain circuits related to memory (both explicit and implicit).

Stimulants cause permanent long-term brain changes, even after years of abstinence. In a study by McCann, it was found that the number of dopamine receptors of chronic methamphetamine users had decreased markedly and this receptor deficit persisted after 3 years of abstinence.

The loss of dopamine receptors increases the risk of these people suffering from Parkinson's when they are older.

Behavioral effects

The main effects are euphoria and increased energy that usually results in increased activity and verbiage.

At high doses, it causes a very intense sensation of pleasure that consumers describe as better than an orgasm, but if the amount is increased, tremors, emotional lability, agitation, irritability, paranoia, panic and repetitive or stereotyped behaviors can occur.

At high doses it can cause anxiety, paranoia, hallucinations, hypertension, tachycardia, ventricular irritability, hyperthermia and respiratory depression.

An overdose can lead to heart failure, stroke, and seizures.

Data of interest

Does it produce dependency?

Stimulant drugs produce both physical and psychological dependence since they not only activate the reward system during intake, they also modify it in the long term.

Does it produce tolerance?

Yes, the chronic administration of stimulants makes modifications in the reward system that adapts to the increase in the concentration of dopamine and becomes habituated, for which the system needs more and more dopamine to activate itself and the person will have to take a dose higher to be able to feel the effects of the drug.

Does it cause withdrawal syndrome?

Indeed, the changes produced in dopaminergic neurons due to their overactivation cause unpleasant symptoms when the drug is not consumed.

This over-activation can cause axonal degeneration and neuronal death, causing symptoms similar to those of the disorder called burn-out, which is usually associated with high levels of stress for prolonged periods.

The withdrawal symptoms include drowsiness and anhedonia (lack of pleasure from any stimulus), and in the long term, loss of cognitive efficiency, depression and even paranoia.

These effects make the person look for the drug with great impetus, putting aside their duties and putting themselves and the people around them in danger.

It is also usual for them to seek extreme pleasurable sensations to be able to feel some pleasure, since due to anhedonia it is difficult for them to feel it, this can make them carry out compulsive behaviors such as unprotected sex and without any type of discrimination.

Can they be used as therapeutic agents?

Amphetamine can be used to treat sleep disorders, especially those related to sleepiness problems during the day, and to alleviate ADHD symptoms.

If you want to know more about this type of drug, I recommend the following video:

Legal drugs: nicotine and alcohol

The nicotine is extracted from the leaves of the snuff is usually administered in cigarettes which carry many toxic and carcinogenic components, such as tar, which damage to the heart, lungs and other tissues.

In addition, when burning it, other compounds are created through chemical reactions that are highly dangerous, such as carbon monoxide and hydrocyanic gas. Spain is the ninth country in the European Union (EU) with the highest percentage of smokers, 29% of the population smokers.

The Alcohol is taken as alcoholic beverage can be made by fermentation or distillation. It is a legal drug in all countries except the Islamic states.

Many people who suffer from any disease or disorder take it to "self-medicate", to be dazed and not think about their problems, therefore alcoholism is a disease comorbid with many other disorders.

According to the WHO, in Spain we drink around 11 liters per year per person, well above the world rate of 6.2 liters per year per person.

Brain effects

Nicotine acts on the nicotinic receptors of the acetylcholine network and, in high doses, promotes dopamine secretion. In addition, another of the components of tobacco is a monoamine oxidase inhibitor (MAOI) that prevents dopamine from being destroyed, which affects the reward system.

Alcohol acts on GABA receptors, enhancing its inhibitory action on the central nervous system and causing a general brain slowdown. In addition, it also acts on glutamatergic synapses, canceling its excitatory action, which would increase the depression of the central nervous system.

It also acts on the reward system by binding to opioid and cannabinoid receptors, which would explain its reinforcing effects.

Behavioral effects

Nicotine has activating and mental alerting effects, contrary to popular belief it has no relaxing effect. As will be explained later, what happens is that if a person addicted to tobacco does not smoke, they will suffer from the "monkey" and to calm them they will need to smoke again.

Alcohol is a depressant of the central nervous system, this produces relaxation, drowsiness and decreased reflexes, at a cognitive level it causes social disinhibition, which is why it is usually taken at social gatherings and parties.

Data of interest

Do they produce dependency?

Both nicotine and alcohol produce physical and psychological dependence. Nicotine produces long-term changes in cholinergic receptors and alcohol in GABAergic receptors, this explains the physical dependence they cause. Psychological dependence is explained because both substances act on the reward system.

Do they produce tolerance?

Yes, both drugs cause tolerance by promoting the interval between taking and taking it to be shorter and shorter and the doses to be higher and higher.

Do they cause withdrawal syndrome?

Indeed, both cause an intense withdrawal syndrome.

When a smoker begins to smoke a cigarette, the reward system kicks in and begins to secrete dopamine, which gives him pleasure.

But when you finish the cigarette, the dopamine receptors are de-energized to adapt to the amount of dopamine, so that they temporarily become inactive and you begin to suffer the typical nervousness of withdrawal.

This inactivation lasts about 45 minutes (the average time it takes a smoker to light the next cigarette), so there are 20 cigars in each pack, so it can last a full day.

As alcohol slows down the brain by stimulating GABA receptors, the body itself defends itself by eliminating these receptors to attenuate their inhibition. In this way, when the person no longer drinks alcohol, they have fewer GABA receptors than normal.

Which causes nervousness, tremors, anxiety, confusion, drowsiness, sweating, tachycardia, high blood pressure, etc. This can cause delirium tremens and a memory disorder associated with alcoholism, Korsakoff syndrome.

If you want to know more about this type of drug, I recommend the following video:

Designer drugs: hallucinogens and ecstasy

The main designer drugs are LSD (or acid), mescaline, PCP (or angel dust), ecstasy (MDMA), and ketamine. These drugs cause an intoxication, which is usually called "trip", which is associated with sensory experiences, visual illusions, hallucinations and an increase in the perception of both external and internal stimuli, this type of effect is called psychedelic.

These types of substances are often called "disco drugs" since they are often used in that context.

Brain effects

Hallucinogens can be of two types, those that mainly affect the serotonergic system (such as LSD) and those that primarily affect the noradrenergic and dopaminergic systems (such as amphetamine and MDMA). Although in reality all these systems are connected and interact as we will see below.

As an example of how hallucinogens act, we will discuss the action of LSD. This compound binds to 5HT2A receptors (serotonin receptors) and causes a hypersensitivity of the perceptions of the senses.

It also affects glutamate, which is an accelerator of brain activity, its activation explains the speed of thinking and reasoning problems. Activation of dopamine circuits explains the feeling of euphoria.

Ecstasy acts on serotonin, an important mood regulator. It blocks the serotonin transporter, preventing its reuptake.

The excess of serotonin causes a feeling of joy and empathy but the serotonin reserves are completely emptied, the neurons can no longer function as before and when this happens the individual feels a kind of sadness and heaviness that can last up to 2 days.

Behavioral effects

The intoxication with hallucinogens can cause visual illusions, macropsia and micropsia, affective and emotional lability, subjective slowing down of time, intensification of the perception of colors and sounds, depersonalization, derealization and sensation of lucidity.

Also at a physiological level it can cause anxiety, nausea, tachycardia, increased blood pressure and body temperature. In states of acute intoxication it can produce symptoms of panic, which is often called "a bad trip", these symptoms include disorientation, agitation or even delirium.

Ecstasy acts on the striatum, facilitating movements and creating a certain euphoria, it also acts on the amygdala, which explains the disappearance of fears and the increase in empathy. In the long term, in the prefrontal cortex it damages serotonergic neurons where it could be neurotoxic, causing irreversible damage that could lead to depression.

Overdose of these substances can cause extremely high temperatures, seizures, and coma.

Data of interest

Do they produce dependency?

No evidence has been found that they produce physical dependence, but psychological ones.

Do they produce tolerance?

Yes, and tolerance builds up quickly, sometimes after just one dose.

Do they produce withdrawal syndrome?

No evidence has been found that they cause withdrawal symptoms.

Can they be used as therapeutic agents?

Yes, they can be used, for example, to help patients suffering from post-traumatic stress syndrome since by acting on the amygdala it does so on fear and reduces or eliminates it while its effect lasts, which would give people some time with this syndrome to treat and face fear without stress.

The downside of this is that, even in small doses, ecstasy is neurodegenerative for the brain.

Articles of interest

Drugs consequencies.

Types of stimulant drugs.

Types of addictive drugs.

Hallucinogenic drugs.

Inhalant drugs.

Causes of drug addiction.

Effects of drugs on the nervous system.

References

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