Types of antipsychotics (or neuroleptics) and their characteristics

Neuroleptics used against psychotic disorders can be classified.

There is a great diversity of theories and hypotheses about psychotic disorders, their causes and how to treat them.There is a great diversity of theories and hypotheses about psychotic disorders, their causes and how to treat them. These disorders cause great harm to those who suffer from them, and produce a strong distress both for the person himself and for those around him. They interfere in cognitive abilities, social relations and in the emotional sphere, altering the contact with reality. Being disorders that limit the normative functioning of the human being, it is essential to treat them..

Based on the research carried out, several substances and active ingredients that can help to treat this type of problems have been developed from a psychotropic drugs perspective. These are the different types of antipsychotics or neuroleptics..

Psychotic disorders

For most people the word schizophrenia is not unfamiliar. It refers to one of the main and best known psychotic disorders, a group of disorders characterized by the presence of perceptions, ideas and behaviors far from the normative, usually with some loss of contact with reality..

This type of disorder usually involves two types of symptoms: positive symptoms, which provoke or add something to the usual behavior, perception or flow of thought, and negative symptoms such as those that flatten and produce a deficit in the psychosocioemotional state of the sufferer.

The most typical and well-known examples of symptoms of psychotic disorders are the presence of abnormal perceptions or hallucinations and the presence of more or less structured belief systems, the so-called delusions. Although the negative symptoms are less visible, the following stand out loss of logic and coherence in thought, poverty of language and poverty of thought or alogia. or alogia.

Let us now focus on one of the forms of treatment, the pharmacological, reviewing the different substances that are used in the presence of psychotic symptoms.

Mechanism of action of neuroleptics

The drugs used to combat the symptoms of psychotic disorders are called antipsychotics or neuroleptics. Formerly known as major tranquilizersThis type of drug combats with great success the typical symptoms, especially those of the positive type.

This type of psychotropic drug focuses mainly on the neurotransmitter known as dopamine, due to the high level of relationship found between this neurotransmitter and the neurotransmitter dopamine. high level of relationship found between this hormone and psychotic symptoms..

Specifically, it has been contemplated that an excess of dopamine in the mesolimbic pathway causes the presence of positive symptomatology such as hallucinations and delusions.whereas a dopaminergic dopaminergic deficit at the mesocortical level is the most probable cause of negative symptomatology such as poverty of thought and alogia. This is why the mechanism of action of the drugs that treat these problems will focus on working with dopamine at the level of its synthesis, reuptake and transmission. However, among the different types of antipsychotics there are differences and nuances in the way they work, as we will see.

In addition to the treatment of psychotic disorders, some neuroleptics have been used for other types of problems, such as some motor, affective or personality disorders (for example in the case of borderline disorder).

Types of antipsychotics

Traditionally, antipsychotics or neuroleptics have been classified into two main groups, classical or typical neuroleptics and atypical neuroleptics.

1. Classical or typical antipsychotics

Discovered by chance in the 1950s, typical antipsychotics are those with which the pharmacological treatment of psychotic disorders was initiated.. This type of medication works by blocking the dopamine D2 receptors of the mesolimbic pathway, reducing the excess of this hormone in the system and causing the cessation of positive symptomatology.

Within this group of antipsychotics we find some well-known ones we find some as well known as haloperidol, chlorpromazine or levomepromazine, together with others such as pimoxazole and pimoxazole.along with others such as pimozide, zuclopenthixol or fluphenazine. They can be administered both directly and in depot form, in which the substance is injected into the muscle in crystallized form in such a way that it is slowly released over time (in cases where there is little will to take the medication or little control over treatment follow-up).

However, despite their great usefulness, typical neuroleptics are non-specific, so that the blockade of dopaminergic receptors does not occur only in the mesolimbic pathway. This causes other pathways that also depend on dopamine to be altered, affecting the mesolimbic pathway as well.This also affects the mesocortical pathway, from which the negative symptomatology apparently arises due to a dopamine deficit. Because the classical neuroleptics act by blocking its uptake, the typical antipsychotics have virtually no effect on negative symptoms, and may even worsen them..

Adverse effects

In addition to this, other pathways such as the nigrostriatal and tuberoinfundibular pathways, which in psychotic disorders need not be altered per se, also have their dopamine uptake inhibited, which can lead to adverse effects in the form of movement disorders such as akathisia, Parkinsonian syndrome and dyskinesia. adverse effects may arise in the form of movement disorders such as akathisia, parkinsonian syndrome and dyskinesia, or sexual disturbances such as dopamine uptake.or sexual disturbances such as amenorrhea or gynecomastia. These symptoms are not only bothersome, but can lead to neuroleptic malignant syndrome, which could lead to death. For this reason, it is necessary to carefully regulate the consumption of these drugs, following the prescriptions of the professionals and being able to change the antipsychotic in order to reduce the discomfort and adverse effects.

It is for this reason that the subsequent research focused on investigating and to develop other antipsychotics that would have a positive effect on negative symptoms and would not produce as many side effects.. This does not mean that typical antipsychotics are no longer used, since they are very effective and adverse symptoms can be controlled with other medication (antiparkinsonian drugs for motor problems, for example).

2. Atypical antipsychotics

In view of the poor effect of conventional antipsychotics on negative symptoms and the high number of unwanted side effects they entail, subsequent research has attempted to create new substances that make up for the shortcomings of this type of neuroleptic, creating safer and more effective drugs. These safer drugs have been labeled as atypical neuroleptics or antipsychotics..

Atypical antipsychotics include substances of different families and compositions, so that depending on which one is used, it will have a greater or lesser effect on various problems. The main drugs that fall into this category are clozapine, olanzapine, olanzapine, clozapine and are clozapine, olanzapine, risperidone, sulpiride, quetiapine and ziprasidone..

Differences from classical neuroleptics

As with conventional antipsychotics, atypical antipsychotics work by blocking dopamine D2 receptors, thus having an inhibitory effect on the mesolimbic pathway of this neurotransmitter, resulting in the cessation of positive symptoms. However, in addition to this, atypical antipsychotics have an effect on serotonin, also producing an antagonistic effect on the mesolimbic pathway.They also produce an antagonistic effect with respect to serotonin.

It is necessary to take into account that serotonin acts as an inhibitor of dopamine release. Thus, the effect that atypical antipsychotics have on the tuberoinfundibular and nigrostriatal pathways (which would be affected by a conventional neuroleptic) generates an interaction between dopamine and serotonin that would leave the dopamine level equal or close to what would be normal. In other words, the presence of possible adverse effects is greatly reduced..

However, given that in the cerebral cortex there are more serotonin receptors than dopamine receptors, inhibiting serotonin causes an increase in the release of dopamine by stopping its release. That is to say that although part of its functioning blocks the release of dopamine, the fact that an inhibitor of its release that is much more present and widespread is inhibited causes the total level of dopamine to be higher. For this reason, atypical antipsychotics do have an effect on negative symptoms by increasing the gross level of dopamine in the mesocortical pathway. in the mesocortical pathway.

All in all, the atypical neuroleptics are a breakthrough that produces improvement in both positive and negative symptoms and generate fewer adverse effects (although they do have some).

Risks and side effects of taking antipsychotics

We have briefly mentioned that taking antipsychotics can cause a variety of undesirable side effects, some of which are various undesirable side effects, some of which are particularly dangerous.. This phenomenon occurs with all psychotropic drugs, since each body is different and it is not known exactly how the active ingredient will interact with the body. This is why it is essential to have medical supervision, to detect these problems in time and to propose alternatives.

These effects can be controlled by taking other medications or by changing neuroleptics, but the possible effects and the occurrence of adverse effects after administration should be evaluated. Some of the main risks and side effects of the different types of antipsychotics are as follows.

1. Motor symptoms

One of the pathways secondarily affected by antipsychotics is the nigrostriatal pathway, which is linked to motor control.

Thus, it is common for extra motor syndrome to appear, extrapyramidal syndrome is common.This syndrome, in which symptoms such as Parkinson-like tremors, the appearance of involuntary movements in tardive dyskinesia, the disappearance of spontaneous movements in akinesia or the motor restlessness of akathisia appear frequently. These symptoms occur mainly with conventional or typical antipsychotics, and are not frequent with atypical antipsychotics.

2. Sexual symptoms

The intake of certain neuroleptics may cause different sexual symptoms, usually due to involvement of the tuberoinfundibular pathway (especially the pituitary gland). (especially in the hypophysis). Within this type of symptoms, the cessation of menstrual flow or amenorrhea stands out, as well as galactorrhea or emission of milk from the breasts, regardless of sex, and gynecomastia or breast growth, also regardless of the patient's sex. Although they generally only occur with typical antipsychotics, there are some cases with certain atypical antipsychotics, such as risperidone..

3. Sedation

As we have seen, one of the original names for antipsychotics is major tranquilizers. This term was not given by chanceThe fact is that taking antipsychotics produces a sedation effect that can be more or less powerful.

4. Neuroleptic Malignant Syndrome

This syndrome is one of the most serious side effects that can be caused by taking antipsychotics and can lead to coma or even death. It is characterized by tachycardia, arrhythmias, high fever, muscle rigidity and loss of consciousness.a. However, it is a very rare syndrome.

5. Agranulocytosis

Described in the case of clozapine, this possible side effect is serious in that it causes red and white blood cell levels to become uncontrolled. It can be lethal, so blood tests are necessary as a control method.

6. Other symptoms

In addition to the above symptoms, it is possible to encounter other problems such as weight gain, excessive salivation, tachycardia or dizziness.