Analysis finds schizophrenics have thinner cerebral cortex, on average

June 6, 2018 by Latina Emerson, Georgia State University
Credit: Georgia State University

Individuals with schizophrenia, on average, have a thinner cerebral cortex, the largest part of the brain that controls higher intellectual functions and motor activity, compared to healthy people, according to an international study co-led by Georgia State University and the University of California, Irvine.

Schizophrenia is a severe mental disorder that affects how a person thinks, feels and behaves. It is one of the top 15 leading causes of disability worldwide, and symptoms include psychotic symptoms, such as hallucinations, delusions and unusual ways of thinking, as well as reduced expression of emotions, difficulty in social relationships and cognitive impairment. The mental disorder is typically diagnosed in the late teens to early 30s and tends to emerge earlier in males. Because the causes of are still unknown, treatments focus on eliminating the symptoms of the disease, according to the National Institute of Mental Health.

The study, the largest meta-analysis of and surface area differences in schizophrenia, was conducted by the Enhancing Neuro Imaging Genetics Through Meta Analysis (ENIGMA) Schizophrenia Working Group, a collaboration of schizophrenia researchers from all over the world. Brain abnormalities are widely reported in schizophrenia, but studies can disagree in their findings. The meta-analysis – a statistical procedure for combining data across multiple studies – uses the data already collected from these studies to identify more powerfully how irregularities in cortical thickness and surface area are related to schizophrenia.

The international research team analyzed data from 9,572 participants, including 4,474 individuals with schizophrenia and 5,098 healthy volunteers. The study combined data samples from 39 centers worldwide, which already had neuroimaging data on individuals with and without schizophrenia. Each site processed structural scans for their study participants using the same methods and statistics, and researchers submitted the results to the ENIGMA Schizophrenia Working Group to be evaluated as part of the larger meta-analysis.

"This is the largest meta-analysis on cortical brain effects in individuals with schizophrenia ever published, and this is the largest collaborative group working on this topic," said Dr. Jessica Turner, senior author of the study and associate professor of psychology and neuroscience at Georgia State. "Our main take-home finding is we are seeing brain regions that are thinner in the schizophrenia group pretty much everywhere in the brain, with the largest effect sizes being in the inferior and superior temporal cortex. Interestingly, even with so many data points and the ability to find very small differences between the groups, the areas around the visual cortex, pericalcarine cortex, were not affected."

In this study, the researchers found the largest differences between schizophrenic and non-psychotic individuals in the frontal and temporal lobe regions of the brain. The frontal lobe plays vital roles in memory, attention, imagination, motivation and other daily tasks, and the temporal lobe includes areas involved in hearing, language, naming and memory, among others.

They also found cortical thickness in several regions was significantly associated with greater severity of schizophrenia symptoms, an earlier age of onset of schizophrenia or longer duration of illness. Compared to controls, individuals who were on first- or second-generation antipsychotic medications generally showed a thinner cortical thickness than individuals who were unmedicated. However, the researchers note this finding should not be used as a reason to withhold these drugs in treating severe mental illness, including schizophrenia, because they are the most effective treatments. The result, they said, should be used as a motivation to examine why that correlation exists. The findings are published in the journal Biological Psychiatry.

The researchers report that the major strength of this study is its large sample size, which provides sufficient power to detect even small effects. This group has already published the largest studies of subcortical volumes in schizophrenia, as well as white matter tracts, and meta-analyses of the relationship of cortical volume and symptom severity (Kelly et al., 2017; van Erp et al., 2016; Walton et al., 2017; Walton et al., 2018). The is also examining more subtle symptom questions, the role of family or early childhood events and other brain measures, and it is collaborating with other ENIGMA working groups focused on major depression and bipolar disorder.

Explore further: Brain connections in schizophrenia

More information: Theo GM. van Erp et al. Cortical brain abnormalities in 4474 individuals with schizophrenia and 5098 controls via the ENIGMA consortium, Biological Psychiatry (2018). DOI: 10.1016/j.biopsych.2018.04.023

S Kelly et al. Widespread white matter microstructural differences in schizophrenia across 4322 individuals: results from the ENIGMA Schizophrenia DTI Working Group, Molecular Psychiatry (2017). DOI: 10.1038/mp.2017.170

Subcortical brain volume abnormalities in 2028 individuals with schizophrenia and 2540 healthy controls via the ENIGMA consortium, Molecular Psychiatry (2015). DOI: 10.1038/mp.2015.63

E. Walton et al. Positive symptoms associate with cortical thinning in the superior temporal gyrus via the ENIGMA Schizophrenia consortium, Acta Psychiatrica Scandinavica (2017). DOI: 10.1111/acps.12718

E. Walton et al. Prefrontal cortical thinning links to negative symptoms in schizophrenia via the ENIGMA consortium, Psychological Medicine (2017). DOI: 10.1017/S0033291717001283

Related Stories

Brain connections in schizophrenia

March 9, 2018
Executive cognitive functions—abilities that include working memory and underlie mental control and self-regulation—are impaired in schizophrenia. Current pharmacological and behavioral interventions have only modest ...

Study identifies brain abnormalities in people with schizophrenia

July 7, 2015
Structural brain abnormalities in patients with schizophrenia, providing insight into how the condition may develop and respond to treatment, have been identified in an internationally collaborative study led by a Georgia ...

Schizophrenia affects your body, not just your brain – new study

May 11, 2018
Schizophrenia is considered a disorder of the mind, influencing the way a person thinks, feels and behaves. But our latest research shows that organs, other than the brain, also change at the onset of the disease.

Cerebellum plays a major role in schizophrenia

June 22, 2017
In a new study, Norwegian researchers have documented that the cerebellum is among the most affected brain regions in schizophrenia. Compared to healthy individuals, cerebellar volume was smaller in patients with schizophrenia. ...

Schizophrenia study identifies shifts in patterns of glutamate and GABA in visuospatial working memory network

January 18, 2018
A new study in Biological Psychiatry has characterized the patterns of brain neurotransmitters glutamate and GABA in a network of regions that temporarily maintain and process visual information about the location of objects ...

Schizophrenia a side effect of human development

February 21, 2018
Schizophrenia may have evolved as an "unwanted side effect" of the development of the complex human brain, a new study has found.

Recommended for you

Linguistic red flags from Facebook posts can predict future depression diagnoses

October 15, 2018
In any given year, depression affects more than 6 percent of the adult population in the United States—some 16 million people—but fewer than half receive the treatment they need. What if an algorithm could scan social ...

Early changes to synapse gene regulation may cause Alzheimer's disease

October 15, 2018
Alzheimer's disease (AD) is the most common form of dementia, involving memory loss and a reduction in cognitive abilities. Patients with AD develop multiple abnormal protein structures in their brains that are thought to ...

Clues that suggest people are lying may be deceptive, study shows

October 12, 2018
The verbal and physical signs of lying are harder to detect than people believe, a study suggests.

Why don't we understand statistics? Fixed mindsets may be to blame

October 12, 2018
Unfavorable methods of teaching statistics in schools and universities may be to blame for people ignoring simple solutions to statistical problems, making them hard to solve. This can have serious consequences when applied ...

From 'problem child' to 'prodigy'? LSD turns 75

October 12, 2018
Lysergic acid diethylamide was labelled a "problem child" by the man who discovered its hallucinogenic properties in 1943: as it turns 75, the drug known as LSD may now be changing its image.

How to avoid raising a materialistic child

October 12, 2018
If you're a parent, you may be concerned that materialism among children has been on the rise. According to research, materialism has been linked to a variety of mental health problems, such as anxiety and depression, as ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.