What Causes Schizophrenia?

If you know someone with schizophrenia, you probably want to know why they have it. The truth is, doctors don’t really know what causes this mental illness.

Research shows it takes a combination of genetics and your environment to trigger the disease. Knowing what increases the chances can help you put together a better picture of your odds of getting schizophrenia.


Think of your genes as a blueprint for your body. If there’s a change to these instructions, it can sometimes increase your odds for developing diseases like schizophrenia.

Doctors don’t think there’s just one “schizophrenia gene.” Instead they think it takes many genetic changes, or mutations, to raise your chances of having the mental illness.

They do know that you’re more likely to get schizophrenia if someone in your family has it. If it’s a parent, brother, or sister, your chances go up by 10%. If both your parents have it, you have a 40% chance of getting it, too.

Your chances are greatest -- 50% -- if you have an identical twin with the disorder.

But some people with schizophrenia have no history of it in their family. Scientists think that in these cases, a gene may have changed and made the condition more likely.

Still, genes aren’t the only thing that matters.

Environmental Triggers

If you were exposed to certain viral infections before you were born, there is some rersearch to suggest that possibly your chances of getting schizophrenia may be higher. This may also be true if you didn’t get proper nutrition from your mom while she was pregnant with you, especially during her first six months of pregnancy. These are both possible theories, but they have not been conclusively proven by scientific studies.

Studies show that taking certain mind-altering drugs called psychoactive or psychotropic drugs, such as methamphetamines or LSD, can expose a person's biological vulnerabilty to devloping schizophrenia. Some research has shown that marijuana use has a similar risk. The younger you start and the more often you use these drugs, the more likely you are to have symptoms like hallucinations, delusions, inappropriate emotions, and trouble thinking clearly.


Schizophrenia and Your Brain

Scientists are looking at possible differences in brain structure and functioning in people with and people without schizophrenia.. In people with schizophrenia, they found:

  • Spaces in the brain, called ventricles, were larger.
  • Parts of the brain that deal with memory, known as the medial temporal lobes, were smaller.
  • There were fewer connections between brain cells.

People with schizophrenia also tend to have differences in the brain chemicals called neurotransmitters. These are responsible for “communicating information” in the brain.

Studies of brain tissue in people with schizophrenia after death even show that their brain structure is often different than it was at birth.

WebMD Medical Reference Reviewed by Joseph Goldberg, MD on August 03, 2018



National Alliance of Mental Illness: “Schizophrenia.”

National Institute of Mental Health: “Schizophrenia.”

Medscape: “Schizophrenia.”

Mayo Clinic: “Schizophrenia.”


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