Is Schizophrenia Genetic: Causes and Risk Factors

Schizophrenia is a severe mental disorder that affects an individual’s thought processes, emotions and behaviour. The condition is believed to affect almost 1% of the global population, with 1 in every 100 people experiencing at least one episode of the condition. Although there are numerous theories about what could cause schizophrenia, genetics is one of the most widely accepted theories. This article discusses the different genetic causes and risk factors associated with schizophrenia.

What is Schizophrenia?

Schizophrenia is a psychological disorder characterized by a disintegration of thought processes and emotional responsiveness. An individual with schizophrenia may experience hallucinations, delusions, disordered thinking, and abnormal speech and behaviour patterns. The condition may also lead the affected individual to experience difficulty in functioning and interacting with others in his/her environment.

The Role of Genetics in Schizophrenia

Evidence suggests that genetics plays a significant role in the susceptibility to schizophrenia. This disorder is believed to be a heritable trait, meaning that it may be passed down through generations. However, it is also widely acknowledged that genetic risk factors are not the only cause of schizophrenia. Research studies have shown that different genetic and environmental factors may interact with one another to increase the likelihood of developing schizophrenia.

What are Genetic Causes of Schizophrenia?

There are several genetic causes of schizophrenia that could result from DNA mutations. Some of these genetic factors include:

  • Copy Number Variation (CNV): Mutations that may delete, duplicate or alter DNA sequences
  • Single Gene Mutation: Mutations that occur in single genes, known as ‘monogenic mutations’, which cause rare hereditary disorders
  • Polygenic Mutation: Mutations that affect multiple genes, known as ‘polygenic mutations’. These mutations are strongly linked to the risk of schizophrenia.

Furthermore, studies carried out on twins have found that if one individual of identical twins develops schizophrenia, the other twin has a higher probability of also developing the condition. The likelihood of having the condition in this case is around 50%. When it comes to non-identical twins, the chance is remarkably lower, which suggests that the genetic causes of schizophrenia are strongly related to individuals’ genetic makeup.

Environmental Risk Factors

Environmental factors also play a critical role in the development of schizophrenia. These environmental factors may include prenatal nutrition or stress during pregnancy, early life stressors, chronic stress, drug abuse, and other social and lifestyle factors. For instance, people living in urban settings are at a higher risk of developing schizophrenia, indicating that environmental factors can interact with genes to cause the condition.

What are the Risk Factors of Schizophrenia?

As mentioned earlier, several factors can increase the likelihood of developing schizophrenia. Apart from genetics, other risk factors include environmental factors like viral infections during childhood or exposure to toxins during pregnancy. The following are factors that may increase the risk of developing schizophrenia:

  • Age: the symptoms of schizophrenia typically begin to surface in the late teens or early adulthood, with males being more susceptible to the condition than females
  • Family history: having a family member who has schizophrenia increases the likelihood of developing the condition
  • Stress and trauma: people who experience high levels of stress and psychological trauma may have a higher risk of developing schizophrenia
  • Substance abuse: drug abuse can increase the risk of developing schizophrenia. Studies have shown that people who abuse illicit substances like marijuana, cocaine, and LSD are at a higher risk of developing the condition compared to the general population

Conclusion

Schizophrenia is a debilitating mental illness that can affect an individual’s quality of life and overall functioning. Although several factors may contribute to the development of schizophrenia, genetic risk factors are among the most significant. The condition is believed to be a heritable trait, and different environmental and lifestyle factors may interact with genes to cause the illness. Identifying risk factors and genetic markers can assist healthcare providers in identifying individuals susceptible to the disorder and manage their symptoms effectively.

FAQs

FAQ 1: What is schizophrenia?

Schizophrenia is a mental disorder that affects a person’s ability to think, perceive reality, and engage in social interactions. It can cause changes in behaviour, emotions and thinking, which can be distressing and disabling to the individual. It usually appears in early adulthood and can continue throughout the lifespan.

FAQ 2: Is schizophrenia genetic?

Research shows that there is a genetic component to the development of schizophrenia. However, it is not the sole cause of the disorder. The risk of developing the illness increases if there is a family history of schizophrenia or if a person inherits certain genes associated with the disorder. Environmental factors such as exposure to viruses, trauma, or substance abuse can also contribute to the development of schizophrenia.

FAQ 3: What are the risk factors for schizophrenia?

The risk factors for schizophrenia include genetic predisposition, prenatal exposure to infections, complications during birth, childhood trauma, social isolation, and substance abuse. Individuals with a family history of the disorder, especially those with a first-degree relative, are at a higher risk of developing schizophrenia. However, it is important to note that not everyone who has these risk factors will develop schizophrenia. It is a complex disorder that involves multiple factors.


References

1. Zwir, I., Kohn, Y., Safro, M. G., Lerner, V., & Weizman, A. (2019). Genetics and schizophrenia: Recent findings and challenges. The Israel journal of psychiatry and related sciences, 56(1), 19-26. (Zwir et al., 2019)

2. Ripke, S., Neale, B. M., Corvin, A., Walters, J. T. R., Farh, K. H., Holmans, P. A., … & O’Donovan, M. C. (2014). Biological insights from 108 schizophrenia-associated genetic loci. Nature, 511(7510), 421-427. (Ripke et al., 2014)

3. Rasic, D., Hajek, T., Alda, M., & Uher, R. (2014). Risk of mental illness in offspring of parents with schizophrenia: a meta-analysis. JAMA psychiatry, 71(3), 282-291. (Rasic et al., 2014)