When you or your loved one live with symptoms of schizophrenia, it may be natural to wonder what caused them.

Schizophrenia can affect anyone, although its symptoms typically show up in late adolescence or early adulthood.

Despite extensive research on it, there are still many misconceptions surrounding the condition. This can make living with schizophrenia even more challenging.

Whether you or someone you love is living with schizophrenia, learning more about the potential contributing factors can give you insight into a mental health condition that affects nearly 1% of the U.S. population and around 20 million people worldwide.

While research continues on this condition, no consensus has been reached regarding the exact causes of schizophrenia.

There’s likely not one cause. Instead, a combination of factors can lead to someone developing symptoms of schizophrenia.

In general, the most understood of factors seem to be related to genes and your environment. Having other mental health conditions may also contribute to developing schizophrenia, but this isn’t true in every case.

In sum, some of the factors that may be involved in the development of schizophrenia include:

  • genetics and biology
  • environmental influences
  • changes in the brain

Does schizophrenia run in families? Not always.

Genetics might play an important role in the development of the condition, even though no specific gene has been identified as its cause.

But a person who has a family history of schizophrenia does have a greater chance of developing the condition:

  • Having a first-degree relative with schizophrenia may increase your chances of developing it by about 13%.
  • If you have an identical twin that has schizophrenia, your likelihood increases to around 44%.

This doesn’t mean everyone who has a close relative with schizophrenia will develop it at some point, just that your chances may be higher.

Most people related to someone living with schizophrenia won’t develop the condition. This is one of the reasons why many experts take environmental factors into account, and not just genetics.

There are some environmental factors that have been associated with a higher chance of developing schizophrenia.

This doesn’t mean that these factors alone lead to an eventual schizophrenia diagnosis, but that they may interact with other factors.

Some environmental factors include:

  • childhood trauma
  • birth and pregnancy complications
  • maternal age (younger than age 19 and older than 40)
  • social isolation
  • migration
  • growing up in urban environments far from green spaces
  • high potency cannabis use

Some experts have theorized that the co-existence of multiple factors might increase the chance of a diagnosis, particularly of early onset.

New technology has allowed doctors to study the brain as you think or move. This is called functional magnetic resonance imaging (or functional MRI).

Some studies have observed changes in brain structure, in both white and gray matter, in people living with schizophrenia.

For example, fluid-filled cavities at the center of the brain, called ventricles, are larger in some people with schizophrenia.

Other observations include:

  • a reduction in the volume of the temporal lobes
  • changes in the white matter connections in the temporal and frontal lobes
  • decreased total brain size

These observations aren’t conclusive, however. Brain changes are usually very minor and may not be found in everyone with schizophrenia. These specific changes can also happen in people without the condition.

There’s also still the question of whether these changes are taking place before or after schizophrenia onset.

Research suggests that if you have schizophrenia, you may be more likely to develop symptoms of other mental health conditions.

These include:

When diagnosing schizophrenia, a health professional will often ask questions and perform tests to eliminate other conditions that might cause your symptoms.

Diagnosis is usually based on a combo of:

  • your medical history
  • your family medical history
  • blood tests to rule out other causes of symptoms
  • a physical exam
  • talking about your concerns and distresses
  • an MRI scan
  • the presence of specific symptoms like hallucinations, delusions, and disorganized speech

What causes schizophrenia hasn’t yet been established, though it may be a combination of genetic and environmental factors.

Changes in the brain may be associated with a diagnosis too, although it’s not clear if these changes are a cause or result of the condition.

The symptoms of schizophrenia can be managed with support, a treatment team, and coping tools.

If you need help finding support, you can check out some of these resources:

If you or someone you know are having symptoms of psychosis, seeking immediate medical care can help you feel better, sooner.