Psychoactive Substances: Characteristics and Types

The psychoactive substances are elements that perform specific changes in brain function. The psychoactive character refers to substance that, when ingested, performs some kind of effect on the central nervous system.

Psychoactive substances can be of multiple types and perform various functions at the brain level, such as inhibiting pain, modifying mood or altering perception.

Likewise, they can be consumed with different purposes. With recreational objectives or with therapeutic objectives. The purpose of the consumption of these substances depends on the intentions of the consumer.

On the other hand, psychoactive substances can be divided between legal and illegal. Some of them are substances whose consumption is accepted by the estates of different states and others are illegal substances.

Psychoactive Substances

The psychological conditions most associated with them are addiction, dependence, abstinence, tolerance and abuse, since most of them can cause some of these reactions in the consumer.

Psychoactive Substances


General characteristics of psychoactive substances

Psychoactive substances are chemical substances that are characterized by acting in the central nervous system.

In this sense, in order to catalog a substance as psychoactive, it is necessary that it be swallowed or ingested and, once administered, make changes in the functioning of the central nervous system.

Psychoactive substances can be both natural and synthetic, and their routes of administration can be varied. They can be administered either orally or parentally, injected, snorted, etc.

The route of administration depends to a greater extent on the qualities of each substance, although many of them can be administered in different ways, depending on the preference of the consumer.

They do not perform specific functions in the central nervous system, but can cause a large number of changes in brain function.

That is, each type of psychoactive substance has a different mechanism of action, acts on different brain regions and causes certain symptoms.

On the other hand, despite the fact that the nomenclature “psychoactive substances” is usually associated with drug addiction or substances of abuse, the reason for the consumption of these substances can be very diverse.

For example, cocaine constitutes a psychoactive substance since its consumption affects the functioning of the central nervous system, and is used for purely recreational purposes.

However, an anxiolytic is also considered a psychoactive substance since its consumption modifies brain function, and it is usually (but not always) used for therapeutic purposes.

In this regard, it is also necessary to emphasize that psychoactive substances include elements that are legal and substances that are illegal.

Continuing with the previous example, cocaine is an illegal psychoactive substance, while anxiolytics are legal psychoactive substances.

This same fact also happens with recreational psychoactive substances such as alcohol or tobacco, which are legal in most countries.

Psychoactive substances vs drug

Although they are two nomenclatures that bear many similarities and are usually used as synonyms, psychoactive substances do not refer exactly to the same elements as drugs.

The definition of psychoactive substance is clear and detailed today. That is, it refers to any type of substance whose consumption generates modifications in the brain functioning of the person.

In this sense, the term psychoactive substances is a broad concept that includes a large number of substances, including drugs.

However, the definition of drugs is somewhat more confusing in today’s society. From the medical point of view and according to the World Health Organization (WHO), a drug is all that substance with the potential to prevent or cure a disease.

In contrast, from the popular point of view and in the colloquial language, the term drug refers to psychoactive substances that are used for recreational purposes and that are illegal.

Thus, psychoactive substances do not refer only to substances with the potential to prevent or cure a disease (medicines) or illegal substances that are used for recreational purposes (illegal drugs).

They refer to all types of substances with effects on the central nervous system (so they include illegal drugs, legal drugs and medicines), regardless of their legality or purpose of consumption.

Basic concepts

The consumption of psychoactive substances can generate multiple cerebral effects in the person. The specific effects depend both on the qualities of the substance and on the form of use and the amount consumed.

In this sense, two different psychoactive drugs such as alcohol or cocaine can generate opposing brain effects. While the first inhibits brain function, the second stimulates it.

However, beyond the specific effects and mechanism of action of each substance, these elements are associated with five main psychological situations: abuse, addiction, dependence, abstinence and tolerance.


Abuse refers to the consumption of a psychoactive substance that is characterized by damaging or threatening the harm of the consumer’s physical or mental health, as well as their social welfare.

In general terms, it refers to a pattern of excessive and certainly impulsive consumption that has negative consequences for the health and well-being of the subject.


Addiction is a psychopathological condition characterized by a pathological search for reward and / or relief through the use of a psychoactive substance.

In general, not all psychoactive substances have to generate addiction in all cases of consumption, although this is usually the case, especially when the psychoactive substance is consumed repeatedly and at high doses.

In general, it is considered that a psychoactive substance generates addiction in the consumer when withdrawal syndrome develops when stopping consuming it.


Dependence on psychoactive substances refers to a set of cognitive, behavioral and physiological symptoms that indicate that an individual continues to consume a substance despite the appearance of significant problems related to it.

That is, the person who develops dependence on a substance requires the effects that this causes in his body to function properly, either at a psychological level, at a physical level or both at a psychological level and at a physical level.


Withdrawal syndrome is a condition that is closely related to the dependence on psychoactive substances.

This condition appears when the dependent subject stops consuming the substance. At that time, you will experience a series of bothersome symptoms, either physically, psychologically or both physically and psychologically.


Tolerance is called the progressive need to administer increasing amounts of a psychoactive substance. This fact occurs due to the “habituation” of the effects of the substance.

That is to say, the organism becomes accustomed to the presence of the psychoactive substance in its interior, reason why each time it requires greater amounts to experience the desired effects.

Types of psychoactive substances

The classification of psychoactive substances is a remarkably complicated process. Psychoactive substances have many different qualities that can motivate different classifications.

First, psychoactive substances can be cataloged according to their origin. That is, they can be divided into natural drugs (which appear spontaneously in nature) and synthetic drugs (which require physical and chemical processes to obtain them).

Another classification used to divide the types of psychoactive substances is the differentiation between hard drugs and soft drugs.

Hard drugs refer to substances that produce serious health risks and soft drugs result in supposedly less dangerous substances.

This categorization has been used especially when defining substances that are used for recreational purposes, but is somewhat more confusing when applied to psychoactive substances in general.

Finally, one of the classifications most used and that allow to better define the characteristics of each psychoactive substance refers to its mechanism of action and, above all, to the cerebral effects produced by its consumption.

In this sense, psychoactive substances can be divided into three main groups: stimulating substances, psychedelic substances and depressant substances.

  1. Stimulants: they refer to all those substances that activate the central nervous system and increase its activity. The main stimulating substances would be cocaine, amphetamines, nicotine and caffeine.
  1. Psychedelic : they are also known as hallucinogenic substances since their main cerebral effect falls on the alteration of perception. LSD, psilocybin or ketamine would be some examples.
  1. Depressants: are substances that act on the central nervous system decreasing its degree of activity and enhancing inhibition. The most commonly consumed depressants are alcohol, barbiturates and benzodiazepines.

Despite its usefulness, this classification is too general, since there are substances belonging to the same classification entity that may present important differences. In this sense, Goldsetin presented a more detailed classification composed of:


Nicotine is a substance that is usually administered in a smoked form. It has a hepatic metabolism and acts at the cerebral level stimulating the nicotine receptors and promoting the release of dopamine  and noradrenaline in the brain.

The main effects of the substance are the generation of a strong addiction and the increase of stimulation, increasing attention, memory, concentration and metabolism, and reducing hunger.

Sedative substances

The sedative substances are included within the depressants. They are formed by substances such as alcohol, barbiturates and benzodiazepines. As well as inhalants solvents (gasoline, acetone, etc.), inhalants gases (nitrous oxide) and liquid ecstasy.

Its main brain action consists in increasing the inhibition through the stimulation of the GABA neurotransmitter and its consumption causes effects such as sedation, drowsiness, tranquility and corporal relaxation.

Cocaine and amphetamines

Cocaine and amphetamines, along with other substances such as fenfluramine, phentermine or mazindol are the main stimulants.

Its consumption motivates an increase in brain activity and causes effects such as addiction, increased energy, reduced sleep, body agitation and increased mood.

Synthesis substances

The synthesis substances are all those obtained through chemical processes carried out in laboratories. The main synthetic substances are MDMA, Ecstasy, EDM, WFP and DOB, and they usually generate stimulating effects.


The cannabis is a substance whose active ingredient is tetrahydrocannabinol (THC). Its consumption usually causes perceptive distortions, memory alteration, lack of coordination, depression or drowsiness.


Caffeine is part of the substances of methylxanthines. Acts at the brain level on adenosine receptors and promotes the release of dopamine and noradrenaline.

Its consumption usually generates reduction of the need to sleep, increase of the attention and perceptive abilities and delay of the fatigue.


Psychedelics are psychoactive substances that are characterized mainly by generating hallucinogenic effects in the brain. It is made up of substances such as lysergic acid derivatives, substituted tryptamines or phenylethylamines.

Anabolic sterolds

Finally, anabolic sterolds are synthetic substances similar to testosterone that are used to increase the physical development of the body.

Legal and illegal substances

Currently there are both legal psychoactive substances and illegal psychoactive substances, although the latter seem to be more numerous.

Substances that are not used for any therapeutic purpose and that are legal in most countries are alcohol, caffeine and nicotine.

Also Read: Tolerance to Drugs and Alcohol: What it is and The Types

Likewise, psychotropic drugs (tranquilizers, amphetamines, @nalgesics, benzodiazepines, antidepressants, antipsychotics and barbiturates) are substances that are legal but whose use is limited to consumption with medical prescription as a response to a specific therapeutic plan.