Causes of Schizophrenia

Updated June 13, 2023

​Schizophrenia is a complex mental health disorder arising from a combination of genetic, environmental, and neurobiological factors. Hallucinations, delusions, and disorganized thought are characteristic of schizophrenia. Living with schizophrenia or living with someone who has schizophrenia is challenging, as daily functioning can be severely impaired. For several decades, researchers have studied the causes of schizophrenia and the disease still remains a mystery in many ways. Today, ongoing research continues to unravel the complex relationships between many factors, aiming to enhance diagnosis and develop more effective treatments.

What Research Exists on Causes of Schizophrenia

Extensive research has been conducted on schizophrenia in an effort to identify causes and improve treatment methods. A study conducted by a team of Harvard Medical School researchers in 2016 conducted a genetic analysis of 65,000 people to determine what causes schizophrenia. It was discovered that the risk of schizophrenia increases when specific variants in a gene are passed down from one generation to another. The gene, C4, which has a role relating to the immune system has been identified as playing a key role in brain development abnormalities associated with schizophrenia.

A 2014 study conducted by researchers at the Stanley Center uncovered that more than 100 regions in the brain can determine risk factors for schizophrenia. Several of those genes are connected to the regulation of dopamine, a neurotransmitter responsible for pleasure, motivation, and learning.

Combined research efforts have led to significant breakthroughs in schizophrenic research that suggests that synaptic pruning that occurs during adolescence may be responsible for the onset of schizophrenia. Synaptic pruning is the process where extra neurons and synaptic connections are naturally eliminated by the brain to improve neuronal transmission efficiency. This finding opens doors of hope that in the future treatments that slow down the synaptic pruning process may decrease the risk of developing schizophrenia. The research also helps to explain why people suffering from schizophrenia also have a thinner cerebral cortex.

How Does Schizophrenia Develop?

How does schizophrenia develop, and what research is underway to target or treat schizophrenia that begins in adolescence? In a 2023 study, researchers at the University of Rochester’s Del Monte Institute for Neuroscience said they’re inching closer to discovering a possible treatment target for schizophrenia during the brain’s development in adolescence.

Dopamine neurons connect to the brain’s frontal cortex. These neurons are essential for decision making and cognitive processing. Researchers found that stimulating underperforming neurons in mice providing dopamine to the brain’s frontal cortex strengthened the dopamine system and helped rescue brain structural deficiencies responsible for causing long-term schizophrenia symptoms.

By targeting the critical development window, researchers hope to change how neuropsychiatric disorders like autism and schizophrenia progress. It is known that schizophrenia often manifests in young adulthood. This research shows that dysfunction of the dopamine system occurs during adolescence. So, there’s hope that targeting interventions to rescue underperforming dopamine neurons in adolescence can change how neuropsychiatric disorders like schizophrenia progress.

Factors That Increase Development of Schizophrenia

Although many parts of schizophrenia are still a mystery and the exact cause(es) are still largely unknown, researchers are confident that a combination of brain chemistry, environmental factors, and genetics are contributing factors.

Environmental Factors That Increase Risk of Schizophrenia

Although neither the biological nor environmental causes of schizophrenia are completely determinant to the onset of the mental illness, studies have shown that you are at increased risk if you have experienced any of the following:

• Fetal distress caused by any number of pregnancy related complications including flu, delivery complications, STDs, use of pain killers, excess body weight, celiac disease, and low folic acid.
• High levels of family related stress during childhood.
• Child abuse or other significant childhood trauma.
• Early and excessive use of cannabis or other street drugs.
• Significant nutrient deficiencies during early childhood.
• Excessive exposure to x-ray radiation during early childhood.
• Severe head injury during early childhood.

Substance Use Linked to Schizophrenia

The use of street drugs, including LSD, methamphetamine, and cannabis have been linked with a significantly increased risk factor of developing schizophrenia. A 2005 study conducted by the Institute of Psychiatry in London asserts that 1 in 4 cannabis users face ten times the normal risk factors for schizophrenia. Some researchers believe that the biological interaction between chemicals in street drugs and the delicate balance of chemicals in the brain can potentially cause the onset of the mental illness.

The age at which you use substances is thought to be significant. Using marijuana regularly during early adulthood contributes to the thinning of the cortical lining of the brain. Researchers believe that cortical thinning is much more common if you suffer from schizophrenia. At the very least, street drugs compound the symptoms and challenges of schizophrenia.

Genetic Causes of Schizophrenia

Decades of research conducted by several mental illness experts has concluded that schizophrenia has a significant genetic component. If you have a third degree relative with schizophrenia, you are twice as likely to develop schizophrenia as those in the general population. if you have a second degree relative, you have a several-fold higher incidence of schizophrenia than the general population, and if you have a first degree relative who suffers from schizophrenia, you are significantly more likely to experience schizophrenia.

What are the genetic causes of schizophrenia? There are a number of genes that are believed to contribute to the pathology of schizophrenia, however, none are fully responsible for the mental illness. A specific balance of genetics and environmental factors must exist for the onset of schizophrenia. It is believed that if you have only a few of the genetic predispositions, environmental factors can offset genes and cause schizophrenia. The converse is true as well. If you are dramatically genetically predisposed, only mild environmental factors may trigger the onset of schizophrenia.

Severity of Schizophrenia

Mental illness professionals who specialize in schizophrenia segment the illness into subtypes to help treat the symptoms.

Research conducted over the past few decades have led many schizophrenia experts to begin viewing the illness as a spectrum disorder. People who are diagnosed with schizophrenia must have at least two of the following symptoms for at least a six-month duration.

You may experience different symptoms in different degrees at different times, but it is still considered schizophrenia. Symptoms may improve for periods of time, but the diagnosis remains. The severity of schizophrenia is largely affected by its proximity to other disorders. For example, your symptoms may be more severe if they are coupled with a mood disorder. The schizoaffective disorder includes a combination of psychotic symptoms and depression or bipolar disorder. Your place on the spectrum will be determined by other factors such as substance use, environmental factors, and co-existing mood disorders.

What Exacerbates Schizophrenia

Schizophrenia requires long-term treatment that includes medication, therapy, and lifestyle changes. There are several factors that can cause a decline in people with schizophrenia.

• Extreme Stress. High levels of stress are believed to trigger schizophrenic episodes and cause backslides in treatment. Stress increases the production of cortisol, which is a known trigger.
• Sedentary Lifestyle. Exercise is known to reduce symptoms of schizophrenia and help fight stress. Rhythmic exercise for at least ten minutes each day has been shown to improve symptoms.
• Sleep Deprivation. Lack of proper sleep can trigger schizophrenic episodes.
• Substance Abuse. Drugs and alcohol complicate schizophrenia and worsen symptoms. nicotine has also been shown to interfere with the positive effects of schizophrenia medication.
• Poor Nutrition. Dramatically changing blood sugar levels and nutrient deficiency can cause mood changes and worsen symptoms.

How to Help Someone with Schizophrenia

Even after extensive research into what causes schizophrenia and conversations with doctors, family and friends may struggle to know how they can help someone diagnosed with it. Besides learning how to get schizophrenia treatment and support for their loved one or friend, it is also essential for these individuals to find help and support for themselves.

Schizophrenia is a challenging disorder. It affects everyone interacting with the person diagnosed. Life can be confusing, severely disrupted, chaotic, and unproductive for all concerned. And emotions can veer wildly when everyone is attempting to live normally.

What can family and friends do? What works best in helping someone with schizophrenia?

Ask What You Can Do to Help

This is sound advice that anyone who wants to assist and support someone with schizophrenia can follow. While no one can guess what’s in another person’s mind, asking what help the individual with schizophrenia might find beneficial is extraordinarily powerful.

This may include:

Keep the Focus on Their Feelings, Not What They’re Experiencing

When someone with schizophrenia sees or thinks something you don’t see or can’t believe, it can be unsettling and difficult to know how to react. What should you do or say at a time like this? Despite your uncertainty and not knowing what causes schizophrenia, it is vital that you recognize what they are seeing, hearing, or believing—the totality of their experiences—feel real to them.

In this case, mental health experts recommend focusing on how the person with schizophrenia feels. Avoid discussions or challenges about what is true or accurate. In other words, do not deny the person’s experience. Try saying something like, “That’s scary. Is there someone you can discuss this with?”

Pay Attention to What’s Positive

It’s emotionally devastating to see someone you care about experiencing this disorder. Schizophrenia’s causes are varied, as are the symptoms. Someone diagnosed with schizophrenia may be significantly challenged in thinking clearly. They may have difficulty knowing or understanding what is real and what is not—and be substantially confused by this reality gap. They may also cease self-care, avoid contact with others, and appear listless, lost, and distant.

All these are common schizophrenia characteristics. Still, what you can do is pay attention to what is going well. Notice the positive things in their life. Instead of zeroing in on what the person with schizophrenia cannot do, set a few realistic and achievable goals they can aim for. Remember that this differs from what they choose if they lose interest or seem unmotivated. It is a part of schizophrenia.