Schizophrenia is a chronic and serious mental disorder characterized by disturbances in thinking, perception of reality, and behavior. Patients may lose contact with reality (psychosis), suffer from hallucinations, delusions (false beliefs), have abnormal thoughts and problems with social and work functioning.
Schizophrenia affects approximately 1% of the population and the first symptoms usually appear in adolescence or during youth. It is more frequent in men, who also tend to develop it earlier than in women. The World Health Organization (WHO) estimates that it affects more than 21 million people in the world.
Causes of Schizophrenia
1. Biological theories:
Biological theories, for their part, propose an important genetic component in the origin of schizophrenia, with the prevalence of schizophrenia being higher in children of biological mothers with schizophrenia.
2. Psychological theories:
Psychological theories propose a vulnerability-stress model, where there is an interaction between a possible individual vulnerability in the patient and the level of stress suffered by the same.
Systemic theories, for their part, plan the double bind theory. This theory maintains that the double bind is formed by contradictory messages and that they occur within an intense relationship that the patient cannot avoid or comment on.
3. Neurochemical theories:
At the neurochemical level, there has been talking of a sub-cortical dopaminergic hyperarousal in the mesolimbic pathway (related to the positive symptoms of catatonic schizophrenia; in this case, motor disorders).
Regarding brain alterations, structural alterations detected by a CT scan present in people with schizophrenia (dilation of the third ventricle and lateral ventricles, cerebellar atrophy, inverted hemispheric asymmetry, cortical atrophy, decreased radio density of the tissue in various areas have been proposed of the brain such as the hippocampus, etc.).
4. Viral theories:
Viral infections have also been reported as causes of schizophrenia (although they have never been proven), and neurodevelopmental disorders.
The latter include an alteration in the formation of the brain during pregnancy or childhood, which does not appear until the structures involved have fully matured and a source of stress or significant hormonal changes appears.
Alterations in brain development
In recent years, it has been shown that it could be a neurodevelopmental disease since most neurobiological findings (involvement of the brain pathways related to glutamate, serotonin, norepinephrine, and acetylcholine) are compatible with alterations of early brain development.
Studies with histopathological techniques and neuroimaging techniques, such as magnetic resonance imaging (MRI), have detected abnormalities in the structure of certain brain regions. Other techniques, such as positron emission tomography (PET), have made it possible to observe some alterations in the functioning of the brain of these patients compared to that of healthy people.
Together, these findings support the theory that schizophrenia may have its origin in alterations in brain development very early, specifically during the development of the embryonic brain.
It is known that the risk of suffering from the disorder is greater when there is a family history. However, the presence of history is neither a necessary nor a sufficient condition; many patients do not present them, and many healthy, yes. This indicates that other non-genetic factors also play an important role in the genesis of the disorder. On the other hand, the genetic alterations involved are still not well understood.
Infections of pregnancy and complications of childbirth
It is being studied whether some virus infections that affect the mother during pregnancy may be responsible for alterations in the normal brain development of the fetus. And that, over time, end up triggering diseases. On the other hand, this disorder has been associated with complications during childbirth (trauma, cerebral anoxia).
Consumption of toxic substances
The risk of schizophrenia associated with cannabis use has been confirmed by different studies but there is still much to study. What seems clear is that using this drug during adolescence increases the risk of schizophrenia in predisposed individuals.