Brain Abnormalities in Schizophrenia

Meaning of Brain Abnormalities in Schizophrenia

What does it mean to have a brain abnormality that is connected to a diagnosis of schizophrenia? Studies show that individuals with schizophrenia demonstrate changes in the brain's functioning (biochemical) and structure (brain volume).

The brain areas most affected are usually the prefrontal and medial temporal lobes which play a part in working memory and declarative memory.¹ The biochemical abnormalities most associated with schizophrenia are problems with the neurotransmitters serotonin, dopamine, and glutamate. So how do these abnormalities lead to or contribute to schizophrenia?

Biochemical Brain Abnormalities in Schizophrenia

There are a few biochemicals within our brains called neurotransmitters that are connected to schizophrenia. There is still a lot of research to be done, but here is what researchers have found out about these chemicals. Schizophrenia seems to be a neurodevelopmental and progressive disorder with multiple biochemical problems or abnormalities. The main biochemicals involved are dopamine, serotonin, and glutamate.

Dopamine

Research studies show a strong connection between dopamine and schizophrenia. There are too many receptors accepting dopamine in the brains of those with schizophrenia. Hyper-responsive dopamine receptors can cause hallucinations and feelings of paranoia. Researchers call this connection the Dopamine Hypothesis.

Having high dopamine levels can lead to positive symptoms of schizophrenia, which means something unusual is present that should not be present (like hallucinations, delusions, and disorganized behavior or speech). Too much dopamine action in the brain is connected to these symptoms.

Glutamate

Research studies also show a connection between too little of the neurotransmitter glutamate and negative symptoms of schizophrenia. The glutamate hypothesis is an explanation for schizophrenia that says individuals diagnosed with schizophrenia possess a lack of the neurotransmitter glutamate in certain brain areas (mostly the prefrontal cortex).

Brain Volume Abnormalities in Schizophrenia

Cerebral tissue of the brain is also impacted by a diagnosis of schizophrenia. Significant shrinkage or enlarged fluid-filled areas (ventricles) in the cerebral cortex are common in the brains of those with schizophrenia.

Studies involving brain images of those diagnosed with schizophrenia show decreased gray matter brain volume and enlarged lateral and third ventricles. These brain abnormalities can cause issues with judgment and decision-making since they involve the areas of the brain that control these tasks.

Lateral and third ventricles, Wikimedia Commons

Increased fluid in the brain is part of the reason for these changes in brain volume and size in those with schizophrenia. Excess fluid in the brain can cause issues that range from headaches to more severe issues such as alterations to the immune system.

Brain scans, Wikimedia Commons

Brain Structure and Function Abnormalities in Schizophrenia

The anatomy of the brain plays a large part in understanding schizophrenia and its symptoms. Multiple brain scans of those with schizophrenia show problems in several areas of the brain. The areas most impacted seem to be the prefrontal cortex and medial temporal lobe.

Medial Temporal and Prefrontal Lobes, Wikimedia Commons

The prefrontal cortex is in charge of our planning, problem-solving, and critical thinking skills. When researchers scan the frontal lobes of those with schizophrenia, they discover that there is a large decrease in neural waves in this brain area, which means there is less synchronized neural firing or communication. The disruption of neural network communication is a contributor to symptoms of schizophrenia.

What about other areas of the brain? The thalamus (in the medial temporal lobe) also seems to be involved in schizophrenia. Recently, researchers discovered that when someone experiences hallucinations, the thalamus is overactivated. The amygdala, another important brain area, is overactivated when someone experiences extreme paranoia.

The delicate connections and functions of each part of the brain are so intricate that even the mildest changes can have severe consequences. What causes all of these problems in the brain? Why do each of these brain areas stop functioning properly?

Causes of Brain Abnormalities in Schizophrenia

Research has found two main possible causes of brain abnormalities in those with schizophrenia: prenatal maternal viruses and genetics.

Prenatal Maternal Viruses

Researchers wondered if illnesses that happen during pregnancy can cause problems for the fetus. Researchers wanted to know if the children of pregnant women who had the flu during pregnancy were more likely to develop schizophrenia later on in life. After several studies, they found a connection between these two dynamics. This is an example of an environmental factor associated with the risk of developing schizophrenia.

Are people who are born in highly populated areas (like big cities) at greater risk for developing schizophrenia due to higher rates of viral infections like the flu? Researchers found that both viral transmission and living in a big city increase the risk of developing schizophrenia. These findings provide support for the idea that the environmental factor of viral infections could be a cause of schizophrenia.

Genetic Factors

Can you inherit schizophrenia from your parents? Those with family members who have or had schizophrenia are at much greater risk of developing the disorder. This is called a genetic predisposition. The odds are pretty high: 1 in 10 children born into a genetic line of someone with schizophrenia are likely to develop the disorder.²

Scientists want to know why this is the case. Are there specific genes that increase the risk of developing schizophrenia? While no one factor seems to determine if someone will develop schizophrenia, genetics is a big piece of the puzzle. There are other factors to take into consideration, though. Often there are things like poor nutrition, prenatal viral infections, and maternal stress that interact with a person's genes and activate the genetic factors linked to schizophrenia. This is called epigenetics or gene-environment interaction.