Causes of Schizophrenia

photo, Nyboer C.

Despite a significant amount of research, science has yet to reveal exactly what causes schizophrenia. Some experts believe it is a combination of factors, particularly genetics, brain anomalies, and environmental triggers. Others, however, believe that this complex disorder is actually not a single disorder at all, but several different disorders. This can make pinpointing a cause even more challenging.


Since schizophrenic appears to have a strong hereditary component, it is very possible that a person is born with a genetic predisposition towards developing the disorder. We know that individuals who have an immediate family member with the disorder have a 10% or higher risk of becoming schizophrenic, compared to 1% of the general population 1. However, not all of them do. Whether he/she does develop the disorder may depend on environmental factors which then trigger the development of schizophrenia.

Environmental Factors

There are many different environmental factors which have been linked to the development of schizophrenia. They are not believed to cause the disorder, in and of themselves, but rather may play a role in its development if the person is already vulnerable. Some of these factors include:

  • Complications during pregnancy or birth, such as maternal illness, exposure to certain toxins or viruses such as the flu virus, severe maternal stress or malnutrition early in the pregnancy, or a long labor
  • Serious early childhood infections or a history of seizures
  • Traumatic or highly stressful life situations, usually in childhood up to early adulthood
  • Regular marijuana use 2
  • Brain abnormalities or chemical imbalances
  • Research has shown that some schizophrenics have structural differences in their brains when compared to the brains of normal people. Also, imbalances in brain chemicals known as neurotransmitters likely play a role in many psychiatric disorders, including schizophrenia. Antipsychotic medications typically target either dopamine, or dopamine and serotonin together.

There are many more potential factors which may contribute to the development of schizophrenia. As research on schizophrenia continues, hopefully science will eventually show us exactly what causes this serious psychiatric illness.

written by Dr. Cheryl Lane, PsyD


  1. Schizophrenia at the Merck Manual
  2. Cannabis use and risk of psychotic or affective mental health outcomes: a systematic review.

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