If someone talks to us about mental disorder, probably one of the first words (possibly along with depression) that comes to mind is the one that gives this article its title: schizophrenia .

This disorder is one of the best known and probably one of the most widely published in literature, with traces and stories suggesting from ancient times that different people (who were even considered possessed by spirits) manifested strange visions, thoughts, behaviors and expressions that largely coincide with the symptoms of this disorder. Throughout this document we will talk about what schizophrenia is, how it affects those who suffer it and how it is treated.

What is schizophrenia?

Schizophrenia is one of the most widely known mental disorders, and the main psychotic-type disorder . We are facing an alteration that implies and generates a significant alteration in the life of those who suffer from it, requiring a series of criteria for its diagnosis.

Thus, the diagnosis of this mental disorder requires that for a minimum of six months at least two of the following symptoms are present most of the time (and each for at least one month): hallucinations, delusions, language alterations and disorganizations, catatonia or negative symptoms such as alogia, emotional flattening and/or abulia.

Perhaps the most common and prototypical symptom is the presence of hallucinations, generally of an auditory nature and in the form of voices in the second person, which may be accompanied by self-referential delusions, persecution and theft, implantation or reading of thought .

It is important to note that such hallucinations are not something invented: the subject actually feels them as something external. However, they are often thoughts of their own that are experienced as coming from the outside (it is speculated that they may be due to the disconnection between prefrontal and speech regions that hinders the self-awareness of subvocal speech) or abnormal interpretations of external noises.

Positive and negative symptoms

The symptoms of psychotic type predominant in schizophrenia have been generally grouped in two large categories, positive and negative symptoms, which have different characteristics and effects on the patient.

Positive symptoms would refer to those alterations that involve an exacerbation or alteration of the patient’s capacities and habitual functioning , generally adding to that functioning. An example of this would be hallucinations, delusions and strange behaviour).

As far as negative symptoms are concerned, they will refer to those alterations that suppose a loss of the already existing skills previously. This is the case of alogia or impoverishment of thought, emotional flattening or abulia.

Psychopathology course

Schizophrenia is now considered a chronic disorder. This disorder is usually in the form of a rash , although there are cases in which it does not arise as such but is constantly deteriorating. Psychotic breakouts usually occur, in which positive symptoms such as hallucinations and agitation abound, after which there is usually complete or partial remission.

It is possible for a single psychotic break to occur with complete remission, although there are usually several throughout life. As we have indicated there may be complete remission, but there may also be cases where such remission is partial and symptoms and cognitive impairment remain . This deterioration may remain stable or be in progress (which is why Kraepelin called this disorder early dementia).


Having a schizophrenia can have a number of consequences and create severe difficulties. The set of symptoms described above significantly interfere with the subject’s normal day-to-day functioning in areas such as interpersonal relations, work or academia.

Social interactions are often greatly reduced and affected, and work and even academic ability and possibilities can also be greatly altered, especially if there is a deterioration. Subjects with schizophrenia usually present attentional and information processing problems, especially in those cases that present negative symptoms. Their performance in sustained or selective attention tasks is lower.

In addition, the effect that the diagnosis itself has on the subject must be taken into account: schizophrenia is a disorder that is considered chronic and that is still highly stigmatized today , even by the people who suffer from it. The diagnosis is a very hard and traumatic moment for the subject, and it is possible that depressive symptoms and/or a period of mourning, denial of the diagnosis and opposition to treatment may appear. This last aspect is especially important, since with treatment psychotic outbreaks are greatly reduced or prevented.

Are there types of schizophrenia?

Until relatively recently, within schizophrenia we could find a series of typologies that referred to a predominant type of symptomatology or a form of presentation of the specific disease.

Specifically, we could find paranoid schizophrenia (centered on hallucinations and delusions of a persecutory and referential nature, along with aggression and other disorders), disorganized schizophrenia (whose main characteristic is chaotic and incoherent behavior and thinking, and flattening and emotional inadequacy) or catatonic schizophrenia (in which the most outstanding problems were psychomotor disorders), with mutism and immobility as well as waxy flexibility and agitation), along with the residual (in which the subject had recovered from an outbreak with the exception of some symptoms that remained, generally negative) or the simple (with prevalence of negative symptoms, such as alogia and emotional flattening).

However, in the latest version of one of the most widely used manuals in the world, the DSM-5, this distinction was no longer made in order to bring together all the subtypes in a single diagnostic entity . However, this decision is not shared by many professionals, who criticize this measure. In fact, some people propose that more than schizophrenia, we should talk about disorders of the psychotic spectrum, similar to what has happened with autism.

Hypothesis regarding its causes

The causes of this disorder, like those of many others, are still largely unknown. Despite this, throughout history different hypotheses have been developed about what can trigger schizophrenia .

Biological hypotheses

At the biological level, what is known is that people with schizophrenia have alterations in the levels of dopamine in certain brain pathways. Specifically, those subjects who present positive-type alterations such as hallucinations or delusions present an excess or hyperfunction of dopamine synthesis in the mesolimbic pathway, while negative symptoms have been related to a deficit of this hormone in the mesocortical dopamine pathway. However, the reason for this phenomenon is still unknown.

In the brain, differences have been observed such as less blood flow to the frontal areas of the brain , differences between both temporal lobes and a smaller volume of some structures such as the hippocampus and the amygdala, as well as larger cerebral ventricles.

It has been observed that genetics appears to play a certain role, often with different genes being implicated in the occurrence of the disorder. Research shows that there does appear to be a genetic predisposition linked to a greater vulnerability to suffering from it , although the disorder does not necessarily have to be triggered. It will be the set of vital circumstances that surround the individual that will determine whether or not this predisposition awakens the disorder.

Today, one of the most widely considered hypotheses is that we are facing a problem in neural migration throughout development that generates alterations that end up stabilizing and that would only generate manifestations in the presence of stressors or hormonal changes such as those produced by the passage to adulthood.

Another hypothesis links it to the existence of viral infections during pregnancy, based on the fact that many subjects with this disorder are usually born in winter and that different conditions such as the flu could cause alterations at brain level.

Psychological hypotheses

In addition to the biological hypotheses, there are others of a much more psychological nature that must be taken into account, although these are not necessarily mutually exclusive.

The best known and predominant model that is employed in the psychological explanation of schizophrenia is the diathesis (or vulnerability)-stress model. This hypothesis establishes the existence of a stable and permanent vulnerability, partly biological and partly acquired, to suffering this disorder and to presenting problems of information processing or problems of social competence and stress management. These subjects will face different types of stressors on a daily basis, such as life events or other more permanent circumstances (such as a very critical family environment or one with excessive expressed emotion to which they will have to adapt. But depending on the circumstances, it can happen that they fail in this adaptation and cannot adjust, this ends up generating the trigger of the disorder.

Some of the oldest theories, of a psychodynamic nature and especially linked to paranoid-type schizophrenia, consider that the causes of the disorder can be found in the presence of deep psychic conflicts from which the subject defends himself by means of projection (placing one or some of his own characteristics in another person) and denial of the conflict, which sometimes end up generating the dissociation of the mind with reality. However, these explanations have no scientific value.


Schizophrenia is a chronic disorder that has no recognized cure at the moment, although the symptoms can be treated so that those who suffer from it can lead normal lives and remain stable, preventing outbreaks.

To do this, however, the treatment must be continued throughout the subject’s life cycle in order to prevent the appearance of new outbreaks. In general, the drugs known as antipsychotics are used for this purpose. They act by treating excess dopamine in the mesolimbic pathway and, in the case of those classified as atypical, also improving the negative symptoms by increasing the levels of this hormone in the mesocortical pathway.

We also work from the psychological field, with therapies such as focusing on auditory hallucinations or cognitive restructuring to change cognitions and beliefs (delusions and/or about the disorder itself). Also training in social skills and sometimes counselling and job reinsertion can be of great help in combating the difficulties generated by the disorder. Finally, the psychoeducation of the subject and the environment are fundamental.

Bibliographic references:

  • American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders. Fifth edition. DSM-V. Masson, Barcelona.
  • Santos, J.L. ; García, L.I. ; Calderón, M.A. ; Sanz, L.J.; de los Ríos, P.; Izquierdo, S.; Román, P.; Hernangómez, L.; Navas, E.; Ladrón, A and Álvarez-Cienfuegos, L. (2012). Clinical Psychology. Manual CEDE de Preparación PIR, 02. CEDE. Madrid.
  • Vallina, O. and Lemos, S. (2001). Effective psychological treatments for schizophrenia. Psicothema, 13 (3); 345-364.