From the article:

The study also identified specific brain cell types associated with the genetic patterns.

For the schizophrenia bipolar group, the strongest genetic signals appeared in genes active in excitatory neurons. These neurons transmit signals that activate other brain cells and help different parts of the brain communicate.

In contrast, genetic risk tied to internalizing disorders such as depression, anxiety, and PTSD showed stronger links to oligodendrocytes. These cells help nerve signals travel more efficiently through the brain.

“The findings suggest these ‘support cells’ might play an important role in those conditions,” said Verhulst, research assistant professor and an expert in quantitative and statistical genetics.”

A massive genetic analysis of more than 6 million people is revealing new clues about why mental health disorders frequently overlap.

An international group of scientists has uncovered new evidence explaining why many mental health disorders tend to occur together. By examining genetic data from more than 6 million people, the researchers explored how over a dozen psychiatric conditions may be connected, including depression, anxiety, schizophrenia, bipolar disorder, ADHD, PTSD, and substance use disorders.

The study, published in Nature, was co-authored by Drs. John Hettema and Brad Verhulst of the Texas A&M University Department of Psychiatry and Behavioral Sciences in the Naresh K. Vashisht College of Medicine.