Depressant Drugs: Types, Effects And Mechanisms Of Action

The depressant drugs  are substances that can decrease brain activity. In some cases they are also known as “sedatives” or “tranquilizers” and are used both in healthcare and recreational settings.

With regard to therapeutic uses, we find different drugs that perform depressant activities. For example, anxiolytics , sleep medications, and tranquilizers.

Syringe With Drugs

In the recreational field, the consumption of depressant substances is somewhat less than that of stimulant drugs. This fact is due to the fact that substances that decrease brain activity produce fewer sensations of gratification than those that stimulate it.

Some examples of depressant drugs are heroin, oxycodone, methadone, barbiturates , benzodiazepines, and ethyl alcohol.

Characteristics of depressant drugs

Depressant drugs constitute a group of substances according to the effects they originate on brain function . ANDhe factor that groups these types of substances is the ability to produce a decrease in brain activity.

This first appreciation is highly relevant since the different types of depressant drugs can present important differences.

The substances that reduce the level of brain activity do not have the same origin or the same composition. Alcohol does not share all the characteristics of anxiolytics or heroin. However, it does share an important one; the ability to reduce the level of brain activity.

Thus, when speaking of depressant drugs, reference is made to a large group of different substances with their own characteristics that resemble the effects at the brain level.


Being independent substances, depressant drugs can have very different origins. ANDThis type of substances can be both of natural origin and of synthetic or semi-synthetic origin.

With regard to depressant drugs of natural origin, morphine and codeine stand out. These two substances are highly depressant drugs that are obtained and consumed without the need to synthesize them.

In the field of depressant drugs of semisynthetic origin, heroin stands out, without a doubt. In fact, as the United Notions Against Drugs and Crime Office (UNODC) world report on drugs highlights, heroin has been one of the most widely used drugs in recent years.

Finally, of synthetic origin, we find methadone, a depressant drug that is used mainly to treat the physical symptoms produced by heroin addiction.

Effects of depressant drugs

Although each of the depressant substances has a number of characteristics and, therefore, can produce different effects, these drugs share some effects. TO Although the central nervous system can be depressed through different pathways and to varying degrees of intensity, a number of common symptoms appear when the level of brain activity is reduced.

The effects of depressant drugs can be broadly grouped into two distinct categories. These are the short-term effects and the long-term effects.

Short term effects

The main symptom produced by depressant drugs is slow brain function. By decreasing the activity of the central nervous system , when these substances are consumed, mental functioning decreases.

Apart from the decrease in brain function, the inhibition produced by these substances also affects physical functioning. In this way, after taking depressant drugs, both blood pressure and respiration can be slowed down.

Due to these two effects, these substances often cause difficulties in concentration and decreased attention. Likewise, confusion, fatigue or dizziness also appear frequently.

If the doses are increased, these symptoms may become more noticeable and disorientation, lack of coordination or lethargy may appear. In fact, a clearly visible symptom produced by the effects of depressant drugs is slurring of words during speech.

At a physiological level, various symptoms such as pupillary dilation, difficulties or inability to urinate and, in some cases, fever may also appear.

Short-term effects with high-dose intakes

When the doses consumed are very high, depressant drugs can cause impaired memory , judgment and coordination, irritability, paranoia, visual disturbances and suicidal thoughts.

It should be noted that these substances, whether used for recreational purposes or for therapeutic purposes, have a high addictive potential.

Obviously, not all depressant drugs are equally addictive, since heroin is much more addictive than anxiolytics. However, both types of substances can be addictive if they are used regularly and uncontrollably.

Long-term effects

The long-term effects of depressant drugs are very different and can vary greatly depending on each substance. However, as mentioned above, one of the effects they all share is addiction.

With prolonged use of these substances, tolerance to the drug can develop relatively easily. This means that the body gets used to the presence of the substance and requires increasing doses to achieve the same effects.

This factor is especially relevant in the case of anxiolytics. If these are not used in an uncontrolled way, the person may require increasing doses to alleviate their anxious symptoms.

On the other hand, the long-term use of depressant drugs can cause depression , chronic fatigue, respiratory diseases, sexual problems and sleep disturbances . As dependence on the substance increases, symptoms such as: uncontrollable cravings to consume it, panic attacks , anxiety, and ongoing discomfort when the drug is not used are also common .

When addiction to the substance is very high, what is known as withdrawal syndrome may appear . This alteration appears at all times the substance is not consumed.

The withdrawal syndrome includes symptoms such as insomnia, weakness, nausea, agitation, high body temperature, delusions, hallucinations, and seizures.

Finally, long-term use of depressant drugs can increase the risk of high blood sugar, diabetes, and weight gain.

Types of depressant drugs

The best known depressant drugs are heroin, alcohol, and anxiolytics, however there are many other types. ANDThese substances can be classified into different subgroups: opiates, sedative-hypnotics, volatile inhalants, and ethyl alcohol.

– Opiates

Opiates are the set of substances that are extracted from the juice of the seeds of the poppy or dormant plant.

These plants are grown on a large scale in Asia (Iraq, Iran, Afghanistan, Pakistan, India, China, Burma and Laos). Likewise, in Europe (Balkans), Equatorial Africa (Nigeria), Central America (Mexico and Guatemala) and South America (Colombia, Peru and Ecuador) there are also plantations.

Its action is linked to the presence in the central nervous system and other target organs of specific and saturable receptors. Specifically, we find three types of receptors: mu, kappa and delta.

The action on mu receptors produces general analgesia, sedation, feelings of well-being, respiratory depression and decreased intestinal motility. 

Kappa receptors are found in the spinal cord and when opioids change their function they produce peripheral analgesia.

Finally, the action on the delta receptors produces peripheral analgesia and narcosis.

The drugs that are part of opiate substances are: heroin, methadone, oxycodone and kraton.


It is a substance with high fat solubility, which is why it quickly reaches high concentrations in the central nervous system. It can be consumed both intravenously and smoked and has a high addictive potential.

The first experience produced by its consumption is called in popular slang as “riding the dragon.” It is usually characterized by symptoms such as peer pressure or personal reasons, nausea, vomiting, euphoria, anxiety, and tremor.

At low doses, heroin produces talkative activity, relaxation, pain suppression, drowsiness, apathy, difficulty concentrating , decreased visual acuity, and miosis.

At high doses the effects are accentuated and fatigued breathing, abdominal orgasmic sensation and euphoria appear.


Methadone is a synthetic opioid developed in Germany in 1937 that is used as a drug for the detoxification treatment of drug addicts to heroin.

Its consumption produces effects such as pupillary contraction, respiratory depression, bradycardia, muscle relaxation, release of antidiuretic hormone, constipation, increase in body temperature and increase in blood glucose.


It is a semisynthetic opiate derived from thebine that is consumed as a substance of abuse in the United States, where it is readily available and cheap.

Its effects are very similar to those of heroin and if very high doses are consumed they can cause seizures.


The Kraton is a tree from the tropical forests of Southeast Asia (Thailand and Malaysia).

Its fresh leaves are eaten chewed and used as a narcotic substitute for opium. It is a substance that produces a high addiction and dependence, and causes effects such as intense euphoria, increased strength and energy, and local anesthesia.

– Hypnotic-sedative substances

The sedative-hypnotic substances are made up of 4 different drugs: benzodiazepines, barbiturates , carisoprodol and GHB.


The benzodiazepines  are a group of sedative-hypnotics and depressants of the central nervous system used as anxiolytic drugs substances. In the market they can be found commercialized under different names such as diazepam, oxacepam, clonazepam, etc.

They are agonist substances of the GABA A receptor, a neurotransmitter that inhibits brain function. Its use is limited to the treatment of anxiety, since it reduces anxiety symptoms.

However, its consumption can produce other effects such as dysarthria, apathy, dry mouth, hypotonia or sedation.


Barbituric acid was the first hypnotic synthesized. It is used as a sedative, anesthetic and anticonvulsant and was previously used to produce hypnosis.

This substance activates the GABA receptor, enhancing its response and can cause coma, stupor and even death.


It is a muscle relaxant that produces drowsiness, ataxia , decreased level of consciousness, stupor and incoordination.

At high doses it can also cause agitation, tachycardia, hypertonia and myclonic encephalopathy.


Also known as liquid ecstasy, it is a substance that is used for alcohol addiction and narcolepsy.

In its recreational use, it is consumed through small bottles and produces euphoria, disinhibition and increased tactile perceptions.

– Volatile inhalants

These substances include products for industrial or domestic use, such as glues, glues, dyes, paints, varnishes, lacquers, etc. They are characterized by being volatile and have a highly nonspecific mechanism of action when consumed.

They began to be used for recreational purposes in the 1960s in Mexico and their consumption produces effects such as: excitement, euphoria, dysarthria, ataxia, hallucinations, feelings of greatness, nausea, vomiting, diarrhea, seizures and arrhythmias.

Its long-term use can cause behavioral disorders such as uncontrolled aggressiveness, irritability, hallucinations and psychotic disorders.

Ethyl alcohol

Alcohol is a substance obtained from the fermentation of glucose from the fruit of the genus Sacharomyces . It can also be obtained by fermentation of sugars such as those in cereals. Its route of administration is always oral and its metabolism is usually relatively slow, with progressive absorption.

Its effects vary depending on the doses, since the higher the doses, the greater the effects. Initially, its consumption usually produces motor activation, euphoria and pleasant sensations.

Subsequently, social disinhibition and a clear antidepressant effect are usually experienced. These symptoms are followed by high vasodilation and aphrodisiac effects.

When the intoxication is more intense, there is motor incoordination, sedative and analgesic effects.

Finally, the inhibition produced by this substance produces anesthetic and hypnotic symptoms, and in extreme consumption it can cause coma and death.


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