A network of neural connections is linked to six psychiatric disorders: schizophrenia, bipolar disorder (BD), depression, addiction, obsessive-compulsive disorder (OCD), and anxiety, new research shows.
The researchers used coherence and lesion network mapping to assess whether there was a common brain network common to many psychiatric disorders. In a meta-analysis of nearly 200 studies involving more than 15,000 people, they found that atrophy coordinated these six psychological conditions that were all mapped onto a common brain network.
Furthermore, lesional damage to this network in patients with head injury is associated with the number of psychiatric disorders that patients are diagnosed with post-trauma.
The findings “have big picture potential implications,” said lead author Joseph Taylor, MD, PhD, medical director of transcranial magnetic stimulation at Brigham and Women’s Hospital Brain Circuit Therapeutics, Boston, Massachusetts. Medscape Medical News.
“In psychiatry, we talk about symptoms and define our disorders based on symptom checklists, which are very reliable but have no neurobiological basis,” said Taylor, who is also an associate psychiatrist in Brigham’s Department of Psychiatry.
In contrast, “in neurology, we ask, ‘Where is the lesion?’ Studying brain networks can help us diagnose and treat people with mental illness more effectively, just as we treat neurological disorders,” he added.
The findings were published online on January 12 Nature human behavior.
Beyond symptom checklists
Taylor said that in the field of psychiatry, “we often study disorders in isolation,” such as generalized anxiety disorder and major depressive disorder.
“But clinically, about half of patients meet the criteria for more than one mental disorder,” he said. “These patients can be difficult to diagnose and treat, and there are poor treatment outcomes.”
There is also a “discrepancy” between how these disorders are studied (at one time) and how patients are treated in the clinic, Taylor noted. And there is growing evidence that psychiatric disorders may share a common neurobiology, he added.
This “highlights the potential for developing transdiagnostic treatments based on general neurobiology, not just symptom checklists,” Taylor said.
Previous work has “attempted to map abnormalities to normal brain regions rather than normal brain networks,” the researchers write. Furthermore, “prior studies have rarely tested specificity by comparing psychiatric disorders with other brain disorders.”
In the current study, the researchers “used morphometric brain lesion datasets combined with wiring diagrams of the human brain to derive a convergent brain network for psychiatric disease.”
They analyzed four large published datasets. Dataset 1 was obtained from an activation likelihood estimation (ALE) meta-analysis of whole-brain voxel-based studies comparing mental disorders such as schizophrenia, BPD, depression, addiction, OCD, and anxiety with healthy controls (n = 193). study; a total of 15,892 persons).
Dataset 2 was extracted from published neuroimaging studies that included patients with Alzheimer’s disease (AD) and other neurodegenerative conditions (n = 72 studies). They reported correlations in terms of greater atrophy in patients with these disorders than in control individuals.
Dataset 3 was obtained from the Vietnam Head Injury Study, which followed veterans with and without head injuries (n = 194 veterans with head injuries). Dataset 4 was obtained from published neurosurgical ablation coordinates for depression.
Common neurobiology
Analyzing Dataset 1, the researchers found a reduction in gray matter in the bilateral anterior insula, dorsal anterior cingulate cortex, dorsomedial prefrontal cortex, thalamus, amygdala, hippocampus, and parietal operculum—findings consistent with working with “pricor.”
However, less than 35% of studies contributed to any one cluster; and no cluster was specific to psychiatric versus neurodegenerative comorbidities (drawn from dataset 2).
On the other hand, coordination network mapping is “more statistically robust” (P <.001) results, which was found in 85% of studies. "Psychiatric atrophy coordinates were functionally linked to the same network of brain regions," the researchers reported.
This network was defined by two types of connections as detailed in the following table.
| Type of connection | brain region |
|---|---|
| positive | |
| Negative |
|
“The topography of this transdiagnostic network was independent of statistical thresholds and specific to psychiatric (vs. neurodegenerative) disorders, with the strongest peak occurring in the posterior parietal cortex (Brodmann area 7) near the intraparietal sulcus,” the researchers write.
When lesions from dataset 3 were overlaid on the ALE map and transdiagnostic network to assess whether map damage was associated with the number of post-lesion psychiatric diagnoses, results showed no evidence of an association between psychiatric comorbidity and damage on the ALE map. (Pearson r =.02; P = 766).
However, when the same approach was applied to the transdiagnostic network, a statistically significant association was found between psychiatric comorbidity and lesion damage (Pearson r = -.21; P = 01). A multiple regression model showed that the transdiagnostic, but not the ALE, network “independently predicted the number of post-lesion psychiatric diagnoses” (P = .003 vs P = .1), investigators report.
All four neurosurgical ablative targets for psychiatric disorders were found in the analysis of dataset 4 to “intersect” and align with the transdiagnostic network.
“The study will not immediately impact clinical practice, but it will be useful for practicing clinicians to know that psychiatric disorders commonly co-exist and may share common neurobiology and a convergent brain network,” Taylor said.
“Future work based on our findings could potentially influence clinical trials and clinical practice, particularly in the area of brain stimulation,” he added.
“Exciting New Goals”
Commenting for Medscape Medical News“The next step in science is to combine individual brain imaging, aka, ‘personal connections.’ Group maps to determine meaningfulness.
Oths, who is also a faculty physician at the Center for Anxiety Treatment and Research and was not involved in the study, noted that brain volume abnormalities/atrophy “is an open question as to whether it can be treated and changed in what direction.”
“The strong take-home message from this paper is that brain volume measures from single coordinates are noisy as measures of psychiatric abnormalities, whereas network effects appear to be particularly sensitive for capturing these effects,” Oaths said.
“Abnormal networks in these disorders do not fit easily into known networks from Haitian participants. However, they map well to other databases related to psychiatric disorders and offer exciting new potential targets for potential treatment studies,” he added.
The researchers received no specific funding for this work. Taylor reports no relevant financial relationships. Disclosures by other researchers are listed in the original article. Oathes reports no relevant financial relationships.
Not hum behavior. Published online January 12, 2023. essence
Batya Swift Yasgur, MA, LSW, is a freelance writer with a consulting practice in Teaneck, New Jersey. He is a regular contributor to several medical publications, including Medscape and WebMD, and the author of several consumer-oriented health books, including Behind the Burka: Our Lives in Afghanistan and How We Escaped to Freedom (Memoirs of Two Brave Afghans). sisters who told her their story).
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