Psychiatric disorders are, for the most part, complex conditions, where genetic and environmental factors intertwine, potentially leading to the disorder—or not.
In this blog, we have previously discussed both mental disorders and genetics and their impact on mental health.
Among these conditions, schizophrenia is one of the most influenced by genetics. Schizophrenia is a psychiatric disorder.
Schizophrenia is also one of the most prevalent conditions worldwide. It affects 24 million people, which means one in every 300 individuals.
This disorder impacts how a person thinks and feels, altering their behavior. These are the main symptoms of schizophrenia. The mind becomes partially disconnected from reality, leading to a distorted perception of the surrounding world.
When someone has schizophrenia, their thoughts and behavior become disorganized, making it difficult to maintain a routine, social relationships, and even self-care.
Its name comes from Classical Greek: σχίζειν (skhízein) and φρήν (phrḗn), which translate to “split mind.”
Schizophrenia is a highly heterogeneous disorder, both in its symptoms and recovery prognosis. In medicine, this is never a good thing—the more variation, the more complicated it gets.
In the past, schizophrenia was classified into five subtypes: residual, disorganized, catatonic, undifferentiated, and paranoid schizophrenia. However, this classification has been abandoned, as it is common for a single individual to show characteristics of multiple subtypes.
Additionally, schizophrenia is a mental illness that develops relatively early compared to others. Most people are diagnosed between the ages of 16 and 30, usually after their first psychotic episode. The disorder tends to appear earlier in men than in women. It rarely develops after age 45, and when it does, it is more commonly seen in women.
It is uncommon for schizophrenia to be diagnosed in a child. But, let’s be honest, children have a natural ability to detach from reality, which makes it particularly difficult to identify symptoms in them.
For this reason, although the disease presents the same in both adolescents and adults, it is more difficult to detect in younger individuals. At that stage, behavioral and mood changes do not raise the same concerns as they would in an adult.
Brief Side Note: Let’s not fall into the stereotypical idea of psychosis that movies have created for us. The term psychosis refers to any episode in which a person loses touch with reality.
During such an episode, the affected individual struggles to distinguish reality from fiction, experiencing anything from delusions to vivid hallucinations. Psychotic episodes are common in many mental illnesses but not exclusive to them. Physical brain injuries or certain substances, such as alcohol, can also trigger psychosis.
Another side note: hallucinations and delusions are not the same
Hallucinations are images or sounds perceived only by the affected person; they are not real.
Delusions are firm beliefs held by the affected person, even when they are not true.
Life with Schizophrenia
People affected by schizophrenia also have a higher risk of developing other mental illnesses or substance use disorders. The prevalence in this group is 41% higher than in the general population.
Behavioral alterations not only affect a patient’s social life and make them more vulnerable to addiction, but they also worsen their overall health and quality of life (less physical activity, poorer diet, adverse effects of antipsychotic medications), potentially leading to other physical illnesses.
A recent study demonstrated that all causes of mortality are increased in people with schizophrenia compared to the control group.
On the other hand, there is a wide range of treatment options for schizophrenia. One in three people recovers completely and can lead a normal life.
The primary treatment for schizophrenia involves second-generation antipsychotic medications, such as aripiprazole, brexpiprazole, iloperidone, or olanzapine.
Beyond pharmacology, other therapeutic approaches focus on brain stimulation techniques, including electroconvulsive therapy and magnetic stimulation. Additionally, efforts are made to reduce social exclusion and promote patient integration.
However, this recovery is only a treatment for schizophrenia. At present, there is no definitive cure, as it remains a chronic disorder with a risk of relapse. Schizophrenia does not have a definitive cure.
Statistical and clinical studies on the disorder have confirmed that schizophrenia leads to a decline in quality of life compared to control groups.
As with the vast majority of diseases, the earlier an accurate diagnosis is made, the better the symptom management and prognosis for the patient.
Heredity of Schizophrenia
Schizophrenia is a complex disorder about which we still know relatively little. Its multifactorial nature makes it very difficult to identify the key mechanisms that trigger and sustain it.
Several factors are considered to play a role in its pathogenesis:
- Genetic factors. Without them, we wouldn’t even be discussing the disease.
- Non-genetic factors in neurological development. These range from complications during fetal development to childhood abuse. Many of these factors are believed to mediate epigenetic changes that negatively affect the development of the central nervous system.
- Pathological alterations in different brain regions. Neurological disorders that, indirectly, could trigger schizophrenia.
- Neuroinflammation hypothesis. This theory suggests a model of neuroinflammation caused by abnormal immune system activity. The relationship between the immune system and mental disorders is not new.
- Other unidentified factors. This category includes factors not covered by the previous ones, such as neurotransmitter pathway disruptions.
Focusing on the genetic aspect, studies have demonstrated that schizophrenia has a high degree of heritability. There are a number of genetic variants, both common and rare, that have been proven to be implicated in the disorder.
A classic question we ask in this blog: Is schizophrenia hereditary? Not entirely. It is estimated to have a heritability of around 50%, which is lower than bipolar disorder, for example. There is no single combination of mutations inherited from parents that guarantees whether or not a person will develop the disorder.
However, there is a higher genetic risk that a person can inherit from their parents.
For instance, DiGeorge syndrome (a 22q11.2 deletion) is one of the genetic alterations most strongly associated with schizophrenia. It has been linked to an up to 25-fold increase in risk.
Other genes associated with schizophrenia are those that encode G protein-coupled receptors and those involved in neurotransmitter synthesis. It is no surprise that the same genes implicated in schizophrenia are also commonly suspected in other psychiatric disorders.
One major challenge is that these variants, on their own, contribute only minimally to the overall risk. Schizophrenia is a highly polygenic disorder, meaning that a vast number of genes need to be analyzed to study it properly.
Additionally, it is likely that many genes involved in schizophrenia have yet to be identified. They have not yet been detected or recorded.
Experts believe that, despite all this, epigenetics plays a greater role in schizophrenia than genetics alone.
However, this does not prevent the tellmeGen genetic analysis from making a risk prediction for developing schizophrenia.
