Anyone who has seen pictures or models of the human brain is aware that the outside layer, or cortex, of the brain is folded in an intricate pattern of “hills”, called gyri, and “valleys”, called sulci.
It turns out that the patterns of cortical folding are largely consistent across healthy humans, broadly speaking. However, disturbances in cortical folding patterns suggest deeper disturbances in brain structure and function.
A new study published in the current issue of Biological Psychiatry suggests that schizophrenia is associated with reductions in the complexity of the cortical folding pattern that may reflect deficits in the structural connections between brain regions.
“The cortical folding pattern itself may not be so important, but the disturbances in connections between brain regions implicated by the changes in cortical folding could provide critical clues to deficits in the integrity of brain circuits that contribute to symptoms and functional impairment in schizophrenia,” commented Dr. John Krystal, Editor of Biological Psychiatry.
The study, conducted by an international group of scientists, measured cortical folding using regional local gyrification index values in patients with psychotic disorders, their first-degree relatives, and healthy controls. The patient group included individuals with diagnoses of schizophrenia, schizoaffective disorder, and bipolar disorder.
Local gyrification index is an advanced metric that quantifies cortical folding using a 3-dimensional approach.
Schizophrenia is a group of psychotic disorders that interfere with thinking and mental or emotional responsiveness. It is a disease of the brain. The term schizophrenia, which means “split mind,” was first used in 1911 by Swiss psychiatrist Eugen Bleuler to categorize patients whose thought processes and emotional responses seemed disconnected. Despite its name, the condition does not cause a split personality.
Schizophrenia is a group of psychotic disorders characterized by disturbances in perception, behavior, and communication that last longer than 6 months. (This includes psychotic behavior.) A person with schizophrenia has deteriorated occupational, interpersonal, and self-supportive abilities.
Types of Schizophrenia
Schizophrenia includes the following subtypes:
Paranoid-type schizophrenia is marked by delusions of persecution or conspiracy and is often accompanied by auditory hallucinations.
Disorganized-type schizophrenia is marked by disordered thought processes, manifested in disorganized speech and behavior, and includes flat affect (absence of appropriate emotional responsiveness).
Catatonic-type schizophrenia is marked by extremes in movement and behavior ranging from hyperactive agitation to complete lethargy and immobility.
Undifferentiated-type schizophrenia is a category used when symptoms do not clearly fall into one of the above subtypes.
Residual-type schizophrenia is used to describe patients who have had a history of schizophrenia but whose symptoms have diminished or become less severe.
Source: University of Maryland Medical Center
Senior author Dr. Matcheri Keshavan, a Professor at Harvard Medical School, describes their results: “The main finding was that psychotic disorders are characterized by reduced folding of the cortex in key brain regions such as the cingulate cortex (a brain region involved in thinking and emotions). Reductions in cortical folding may reflect alterations in brain development early in life in these disorders. We also observed these alterations in first degree relatives at high risk for psychotic illnesses.”
With imaging data from 931 participants, this study is one of the largest of its kind and helps to resolve a diverse literature that has produced inconsistent findings, particular in studies of schizophrenia patients. With the consistency of this data in both the patient and relative groups, compared to the healthy group, this study suggests that hypogyria may mark familial risk for psychotic illnesses.
Thus, Keshavan added, “This study lays groundwork for further understanding of the causes of psychotic disorders.”
Schizophrenia is the most persistent and disabling of the major mental illnesses. It usually attacks people between the ages of 16 and 30, as they are beginning to realize their potential. It affects approximately one in 100 people worldwide, (one per cent of the population), affecting men and women almost equally. While it is treatable in many cases, there is as yet no cure for schizophrenia.
The mind controls the basic functions of thinking, feeling (emotions), perception (the five senses) and behaviour. These functions ordinarily work together, enabling us to:
tell the difference between fantasy and reality
keep anxiety at manageable levels
have appropriate emotional responses
make sense of what happens to us
maintain a stable sense of who we are
establish and maintain relationships with others
In schizophrenia, the interaction of these mental functions is disturbed in various ways. The word schizophrenia does not mean “split personality” but a disruption of the balance among mental functions.
The article is “Local Gyrification Index in Probands with Psychotic Disorders and Their First-Degree Relatives” by Pranav Nanda, Neeraj Tandon, Ian T. Mathew, Christoforos I. Giakoumatos, Hulegar A. Abhishekh, Brett A. Clementz, Godfrey D. Pearlson, John Sweeney, Carol A. Tamminga, and Matcheri S. Keshavan (doi: 10.1016/j.biopsych.2013.11.018). The article appears in Biological Psychiatry, Volume 76, Issue 6 (September 15, 2014), published by Elsevier.
Notes for editors
The authors’ affiliations, and disclosures of financial and conflicts of interests are available in the article.
John H. Krystal, M.D., is Chairman of the Department of Psychiatry at the Yale University School of Medicine, Chief of Psychiatry at Yale-New Haven Hospital, and a research psychiatrist at the VA Connecticut Healthcare System. His disclosures of financial and conflicts of interests are available here.
About Biological Psychiatry
Biological Psychiatry is the official journal of the Society of Biological Psychiatry, whose purpose is to promote excellence in scientific research and education in fields that investigate the nature, causes, mechanisms and treatments of disorders of thought, emotion, or behavior. In accord with this mission, this peer-reviewed, rapid-publication, international journal publishes both basic and clinical contributions from all disciplines and research areas relevant to the pathophysiology and treatment of major psychiatric disorders.
The journal publishes novel results of original research which represent an important new lead or significant impact on the field, particularly those addressing genetic and environmental risk factors, neural circuitry and neurochemistry, and important new therapeutic approaches. Reviews and commentaries that focus on topics of current research and interest are also encouraged.
is one of the most selective and highly cited journals in the field of psychiatric neuroscience. It is ranked 5th out of 135 Psychiatry titles and 14th out of 251 Neurosciences titles in the Journal Citations Reports® published by Thomson Reuters. The 2013 Impact Factor score forBiological Psychiatry is 9.472.
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