Types of Psychotropic Drugs: Uses and Side Effects

We review the types of psychotropic drugs, their uses, composition and possible risks.

As we all know, the use of substances with properties that contribute to improve the symptoms of a disease or disorder is a key element in medicine, being used to return the organism to its natural state of balance.

In the case of psychological disorders, the presence of very diverse problems has generated the research of multiple treatment options, among them pharmacological.

What kinds of psychotropic drugs exist and what are they used for?

The fact that there are a large number of different symptoms and disorders has led to the existence of a wide variety of drugs to treat them, divided into different types of psychotropic drugs. None of these categories is, in itself, better than the rest, and their usefulness will depend on each case. However, clinical psychologists and psychiatrists should be familiar with all of them in order to offer the best possible treatment to their patients..

Let us proceed to see below the different types of psychotropic drugs that exist in reality.

1. Neuroleptics/antipsychotics

Mainly used as a method of controlling psychotic crises, this group of psychotropic drugs is used in the treatment of psychotic crises.In the past, this group of psychopharmaceuticals were formerly called major tranquilizers due to the level of sedation that their first versions caused. There are different groups within this conglomerate, exerting an effect mainly on dopamine transmission in distant brain regions.

Within the neuroleptics we can find:

1.1. classical/typical antipsychotics.

The mechanism of action of these substances is based on the blockade of dopamine receptors (specifically D2 receptors) of the mesolimbic pathway, a blockade that causes a cessation of the positive symptoms of schizophrenia and psychotic disorders (hallucinations, delusions, etc.).

However, the action of this type of drugs is not only in the mesolimbic circuit, but affects the rest of the dopaminergic pathways, and can cause side effects in different facets such as movement (e.g. tremors, tardive dyskinesias, restlessness or low spontaneity) or reproduction (emission of milk from the breasts regardless of sex or amenorrhea, among others).

In addition, these drugs have very little effect on the negative symptoms (lack of logic, poor language (lack of logic, poor language, motor and mental slowness), being their effect practically non-existent in this sense. This group includes chlorpromazine, haloperidol and pimozide, among others.

1.2. Atypical antipsychotics

Atypical antipsychotics were synthesized with the aim of also improving negative symptoms and reducing side effects due to the involvement of other pathways. This type of neuroleptic acts by blocking dopamine and serotonin.blocking the latter, thus eliminating the side effects of blocking the former.

Also, given the greater number of serotonin receptors in the cortex and the fact that the latter acts as a dopamine inhibitor, dopamine inhibition causes an increase in dopamine action in mesocortical areas, which leads to an improvement in negative symptoms. Nevertheless, some side effects such as hypotension, tachycardia, dizziness or sedation may occur. In the case of clozapine, there is also a risk of agranulocytosis, an alteration in the red and white blood cell count that can be fatal if not controlled.

Within this group are clozapine, risperidone, olanzapine, quetiapine, sulpiride and ziprasidone. Since they belong to different families, they can have a greater or lesser effect on certain disorders, working not only for psychotic disorders but also for others such as tic disorders, autism, OCD and mood disorders.

2. Anxiolytics and sedative-hypnotics

The presence of anxiety problems is a frequent phenomenon in today's society, being the most frequent type of anxiety disorders.being the most frequent type of disorders. In order to combat it, anxiolytics have been developed.

This type of psychotropic drug acts by exerting a depressant effect on the nervous system, causing a decrease in the level of activity of the person. They generally act on the GABA hormone, enhancing its inhibitory action. Some types of psychotropic drugs included in this classification are used as sedatives, to facilitate sleep, while others are used to simply achieve physical and mental relaxation.

Within this group we can find the following subtypes:

2.1. Barbiturates

This group of psychotropic drugs were the most popular until the discovery of benzodiazepines for treating anxiety. However, the risk of these drugs is that they have a high capacity to cause dependence, and overdose intoxication and even death are not uncommon. In the long term, they may also cause neurological damage.

2.2. Benzodiazepines

The discovery of this type of psychopharmaceuticals helped greatly in the treatment of anxiety disorders, presenting a series of benefits that have made them currently the most marketed psychotropic drugs for anxiety. Specifically, in addition to an immediate effect, they present less health risk than barbiturates, producing fewer side effects, being less addictive and causing less sedation.

In addition to their anxiolytic effect, benzodiazepines are used as sedatives and even as anticonvulsants.. However, in long treatments they can generate dependence as well as abstinence after cessation of their consumption, so that medical prescriptions must be followed rigorously and their intake and withdrawal must be correctly scheduled.

It is a type of substance that favors the inhibitory function of GABA, being indirect agonists of this neurotransmitter. Although they are distributed non-specifically throughout the brain, the cortex and the limbic system are where they are most active.

Within the benzodiazepines there are also different typologies, depending on whether they have long action (they require more time to take effect but have a much longer duration than the rest), intermediate or short action (immediate action and short duration, ideal for panic crises), that is, depending on the half-life of the substance in the organism.

Some examples of benzodiazepines are the well-known triazolam, alprazolam, lorazepam, clonazepam or bromazepam (better known by its trade name, Lexatin).

2.3. Short-acting sedative-hypnotics

Zaleplom, Zolpidem and Zopiclone are the names of three drugs that, like benzodiazepines, act as GABA agonists, act as GABA agonists. The main difference with benzodiazepines is that while the latter act on all GABA receptors, hypnotics only act on receptors linked to sleep, not affecting cognition, memory or muscle function.

Buspirone

This psychotropic drug is used especially in cases of generalized anxiety disorder. Its mechanism of action is centered on serotonin, being a serotonin agonist. Thus, it is one of the few anxiolytics that are not related to GABA receptors. It does not cause dependence or withdrawal. However, it has the disadvantage that the effect of this substance can take more than a week to take effect.

3. Antidepressants

After anxiety disorders, mood disorders are some of the most prevalent disorders in the general population, especially in the case of women.especially in the case of depressions. To treat this problem we have this class of psychotropic drugs, which offer different alternatives. However, the exact mechanism by which they are useful for treating certain disorders is not yet known, and they are not only useful for mood disorders.

In any case, as with any of the other types of psychotropic drugs, antidepressants can only be used under medical indication. The fact that they act primarily on mood does not mean that their influence on the brain is without considerable risk.

3.1. Monoamine oxidase enzyme inhibitors (MAOIs)

The first antidepressants to be discovered, this type of psychotropic drug was found accidentally while searching for a remedy against tuberculosis.. Its operation is based on the inhibition of the enzyme monoamine oxidase, which is normally responsible for eliminating excess monoamines (specifically serotonin, dopamine and noradrenaline).

This type of Antidepressant tends not to be used as the treatment of choice, being reserved for cases that do not respond to other drugs. The reason for this is that they present a high risk of hypertensive crisis, being necessary an exhaustive control of their administration and having to control that certain foods containing tyramine or rich in proteins (such as chocolate, dried fish, cheese, coffee, beer...) are not consumed. It also has other side effects such as possible anorgasmia or weight gain.

Within the MAOIs there are Irreversible and Non-Selective (their function is to completely destroy the MAO enzyme) and Reversible and Selective which only inhibit the function of MAO without destroying it, so if there is a real excess of monoamines the enzyme could work. Examples of MAOIs would be Isocarboxazid and Moclobemide.

3.2. Tricyclics and tetracyclics

Found while researching the development of neuroleptics, this type of psychotropic drug was, until the discovery of SSRIs, the most widely used for the treatment of depression.. Their name comes from their ring-shaped structure. Their action is based on inhibiting the reuptake of both serotonin and norepinephrine, so that these hormones remain longer in the synaptic space having a longer effect. The effects of these drugs begin to be noticed after two or three weeks.

However, apart from their effect on serotonin and noradrenaline, they also affect other hormones, being antagonists of acetylcholine, histamine and blocking some noradrenaline receptors. Therefore, they can cause antihistamine and anticholinergic effects (dry mouth, constipation, blurred vision...). They can also cause death by overdose, so they must be regulated with special caution.

Some famous tricyclic antidepressants are imipramine (used in addition to depression in anxiety disorders and parasomnias) or clomipramine (also used as a treatment for OCD and anorexia).

3.3. Specific Serotonin Reuptake Inhibitors (SSRIs)

SSRIs are a type of psychotropic drug characterized by, as the name suggests, inhibiting the reuptake of serotonin in a specific manner. That is, to prevent serotonin from being reabsorbed so that it is more available and its presence in the brain is prolonged, without affecting other neurotransmitters.

In this group of psychotropic drugs we find fluoxetine (the well-known Prozac), paroxetine, sertraline, fluvoxamine, citalopram and escitalopram.

This is the type of antidepressant with the highest level of safety and the fewest side effects, being the first choice treatment in many cases, and not only for major depression but also for other disorders. Specifically, they are the pharmacological treatment of choice in OCD, as well as in eating disorders (fluoxetine is the most effective in cases of bulimia).

3.4. Selective Noradrenaline Reuptake Inhibitors (SNRIs)

As with SSRIs, the action of this type of drug is based on inhibit the reuptake of a hormone so that it has a greater presence in neuronal synapsesin this case noradrenaline being the neurotransmitter in question. Reboxetine is the most relevant drug in this regard.

3.5. Dual Serotonin and Noradrenaline Reuptake Inhibitors

They act in the same way as the tricyclics, but with the difference that they only affect the neurotransmitters. only affect the neurotransmitters on which they are intended to act.. In other words, they are specific, which eliminates most of the side effects. The example of such a drug currently available is venlafaxine.

4. Mood Stabilizers/Eutimizers

Another major mood disorder is bipolar disorder.. In order to maintain a balanced and stable mood, two basic types of psychotropic drugs are also available:

4.1. lithium salts

Although it is proposed that it produces an alteration of the G protein that modulates the transmission of messages in neuronal synapses, the mechanism of action of this type of psychotropic drug is not yet fully understood. Despite the lack of exact knowledge as to why, this drug has shown a high efficacy in treating manic episodes and maintaining a stable mood..

However, it has the disadvantage that the difference between the amount needed to produce an euphoria-producing effect and the amount needed for intoxication is very narrow, and it is essential to control the lithium level in the blood by means of analysis. It can also produce some side effects such as diarrhea, acne, tremors, hair loss or cognitive loss, so there may be some resistance to treatment.

4.2. Anticonvulsants

Although these drugs were developed to control seizures in cases of epilepsy, studies have shown that they also have a high efficacy in treating bipolar disorder..

They work by promoting the action of GABA and reducing that of glutamate. Mainly used are valproic acid, carbamazepine and topiramate.

Bibliographic references:

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