What is schizophrenia?

Schizophrenia is a severe chronic mental health condition classified as psychosis. It affects how a person thinks, perceive themselves, and behaves, making them seem like they have lost touch with reality. Schizophrenia is not as common as other mental disorders, but the symptoms can be very disabling.

Symptoms of schizophrenia

The most common symptoms of schizophrenia include:

  • Delusions: These are false beliefs that are not based on reality. For example, you may believe that people are plotting to harm you or that the TV is sending you secret messages.
  • Hallucinations: These usually involve seeing, hearing, touching, tasting, or sensing things that aren’t there or don’t exist. For example, you may hear voices that comment on your behavior or tell you to do something.
  • Disorganized thinking (speech): This refers to speech that is hard to understand because it may be jumbled or disconnected from the topic.
  • Extremely disorganized or abnormal motor behavior: This can range from childlike silliness to unpredictable aggression. It also may include resistance to following instructions, inappropriate sexual behavior, and communication consisting mainly of gibberish.
  • Negative symptoms: These are associated with diminished emotional expressiveness and motivation. For example, people with negative symptoms may no longer enjoy their favorite activities, have trouble sustaining attention in conversation, appear unusually flat or expressionless, and sometimes even become unresponsive. Patients may neglect personal hygiene and have difficulty with everyday tasks.

Cognitive symptoms of schizophrenia

In addition to the psychotic symptoms listed above, people with schizophrenia often have cognitive symptoms. These cognitive symptoms can make it hard to remember things, concentrate or pay attention, and use the information immediately after learning it.

Schizophrenia is not a mood disorder, but it often occurs with other conditions, such as bipolar disorder or depression. [1][2]

So, is schizophrenia genetic?

Yes, but only to a certain extent, as many other factors are involved.

The exact cause of schizophrenia is unknown, but it is thought to be caused by a combination of genetic, physical, psychological, and environmental factors. There is not one single gene that causes schizophrenia. In fact, experts believe that many different genes contribute to the development of this mental illness. In addition, experts also say that environmental factors such as stress can trigger the onset of schizophrenia in people with a genetic predisposition to the psychiatric disorder.

While the exact cause of schizophrenia is unknown, evidence suggests it may be inherited. Studies show that people with first-degree relatives (parents, siblings, or children) who have schizophrenia are more likely to develop the disorder than those without any family history.

In other words, if either of your parents have schizophrenia, your chances of developing it are higher (around 1 in 10) than the general population (around 1 in 100). However, remember that just because someone has a family member with schizophrenia does not mean they will definitely develop the disorder themselves. The risk of schizophrenia increases if more than one family member has the condition.

Identical twins have the same genetic makeup, so their differences are environmental. When one twin has schizophrenia, it was found that the likelihood of the second twin developing it was between 40-50%. The unaffected twin likely carries the genetic risk for developing schizophrenia, but it is not necessarily expressed. [3]

Other causes of schizophrenia

Physical causes can increase the risk of developing schizophrenia:

Scientists have identified that genetic changes can interact with environmental factors such as exposure to infections or severe stress during childhood, leading to an increased risk for schizophrenia. This is also true for those experiencing complications during birth, such as premature birth, having a low birth weight, or lacking oxygen during delivery.

People with schizophrenia often have subtle differences in the structure of their brains, leading experts to think that it may partly be a disorder of the brain. [4]

Researchers have identified a link between an imbalance in levels of the chemicals messengers dopamine and serotonin and the development of schizophrenia. Furthermore, deletions and duplications in specific chromosomes are believed to be involved in some cases of the disorder.

For example, a microdeletion present in chromosome 22 called 22q 11 is thought to contribute to a percentage of schizophrenia cases. Of those individuals who carry this deletion, about 30% will develop schizophrenia. This combination of symptoms is recognized as 22q11.2 Deletion Syndrome. [5]

Other triggers that can cause schizophrenia to develop include:

  • Psychological triggers such as high levels of stress, grief, the end of a relationship, and physical, emotional, or sexual abuse.
  • Substance abuse, including misuse of cannabis (especially in teenagers or young adults), cocaine, amphetamines, or LSD. [4]


  1. MedlinePlus. (2018). Schizophrenia. Retrieved December 1, 2022, from https://medlineplus.gov/genetics/condition/schizophrenia/ 
  2. NHS UK. (2019). Symptoms—schizophrenia. Retrieved December 1, 2022, from https://www.nhs.uk/mental-health/conditions/schizophrenia/symptoms/
  3. Gejman, P., Sanders, A., & Duan, J. (2010). The Role of genetics in the etiology of schizophrenia. The Psychiatric Clinics of North America, 33(1), 35–66. https://doi.org/10.1016/j.psc.2009.12.003
  4. NHS UK. (2019). Causes—schizophrenia. Retrieved December 1, 2022, from https://www.nhs.uk/mental-health/conditions/schizophrenia/causes/
  5. Qin, X., Chen, J., & Zhou, T. (2020). 22q11.2 deletion syndrome and schizophrenia. Acta Biochimica Et Biophysica Sinica, 52(11), 1181–1190. https://doi.org/10.1093/abbs/gmaa113