A sweeping analysis of brain chemistry has identified a potential biological signature for anxiety disorders, revealing that people with these conditions have consistently lower levels of the essential nutrient choline in their brains. The study, published in the Nature journal Molecular Psychiatry, synthesizes decades of research and suggests that this chemical difference could open new avenues for understanding and potentially treating these common and debilitating illnesses.

Anxiety disorders, which include conditions like generalized anxiety disorder, panic disorder, and social phobias, represent the most common category of mental illness in the United States. “Anxiety disorders are the most common mental illness in the United States, affecting about 30% of adults,” said Richard Maddock, the study’s senior author and a research professor in the Department of Psychiatry and Behavioral Sciences at the University of California, Davis. “They can be debilitating for people, and many people do not receive adequate treatment.”

These conditions are understood to involve complex interactions between different brain regions. Areas like the amygdala, which acts as a threat detector, and the prefrontal cortex, which helps manage planning and emotional responses, can become dysregulated. This can cause the brain to perceive manageable, everyday stressors as overwhelming threats, leading to persistent worry and nervousness.

The new research comes from Maddock and his colleague Jason Smucny, an assistant professor at UC Davis. Maddock, a psychiatrist who has spent decades treating patients and researching anxiety, had previously observed low levels of choline in his own studies of people with panic disorder. This prompted him and Smucny to investigate whether this was a consistent pattern seen across the scientific literature.

To find an answer, the researchers conducted a meta-analysis, a type of study that systematically combines and analyzes the results of many previous independent studies. This method allows scientists to detect broad patterns that might not be apparent in smaller, individual experiments. They gathered data from 25 separate studies, creating a large dataset that included 370 people diagnosed with an anxiety disorder and 342 people without.

The studies they analyzed all used a specialized, non-invasive imaging technique called proton magnetic resonance spectroscopy. This method uses the same type of machine as a standard magnetic resonance imaging scan, which creates pictures of the body’s internal structures. Instead of producing an image, however, this technique provides a chemical profile of a specific brain region, allowing researchers to measure the concentration of different molecules, known as neurometabolites.

The analysis revealed a distinct and consistent chemical difference. Across the various anxiety disorders, individuals with these conditions had lower levels of choline-containing compounds in their brains. The reduction was most pronounced in the brain’s cortex, the outer layer responsible for higher-order functions like thinking, decision-making, and emotional regulation. The finding was especially consistent in the prefrontal cortex.

On average, the level of choline was about 8% lower in those with anxiety disorders. While this number might seem small, even minor changes in the brain’s chemical environment can have significant effects on its function. “An 8% lower amount doesn’t sound like that much, but in the brain it’s significant,” Maddock said.

The researchers found that this chemical pattern was “transdiagnostic,” meaning it appeared to be a common feature across different types of anxiety disorders rather than being unique to one specific condition. The team also examined whether other factors, such as patient medication, age, or the technical specifications of the brain scans, could explain the results. The link between anxiety and lower choline held firm, suggesting it is a robust biological marker.

The finding became even more defined when the researchers assessed the quality of the measurements in the original studies. In the subset of studies that used the most precise measurement techniques, the reduction in choline was even more apparent. This strengthens the confidence that the observed difference is a real phenomenon and not an artifact of inconsistent data.

The study also looked at other neurometabolites, including N-acetylaspartate, a molecule often used as an indicator of the health and integrity of neurons. After removing a few outlier studies from the analysis, the researchers found a small but significant reduction in this molecule as well, suggesting a possible widespread effect on neuronal function in anxiety.

Choline is an essential nutrient that plays a fundamental part in building cell membranes and producing neurotransmitters involved in memory, mood, and muscle control. While the body can produce a small amount on its own, the majority must be obtained through food.

The researchers propose that the chronic state of high alert, or “fight-or-flight” response, common in anxiety disorders may increase the brain’s metabolic activity. This heightened state could place a greater demand on choline resources to maintain neural circuits, gradually leading to lower overall levels.

It is important to recognize that this study identifies a strong correlation, not a direct cause-and-effect relationship. It is not yet clear whether lower choline levels contribute to the development of anxiety, or if the biological processes of anxiety itself cause choline levels to drop. Further work is needed to untangle this relationship.

Despite these open questions, the finding points toward potential new strategies for patient care. “This is the first meta-analysis to show a chemical pattern in the brain in anxiety disorders,” said Smucny. “It suggests nutritional approaches — like appropriate choline supplementation — may help restore brain chemistry and improve outcomes for patients.”

Future studies will need to test this idea directly. “We don’t know yet if increasing choline in the diet will help reduce anxiety. More research will be needed,” Maddock said. He cautions that people experiencing anxiety should not begin taking high-dose choline supplements on their own, as the effects are not yet understood.

At the same time, the research highlights the connection between diet and mental well-being. A healthy diet is a cornerstone of overall health, and ensuring adequate nutrient intake may be particularly relevant for brain function. Choline is found in a variety of foods, including eggs, beef, chicken, soybeans, and fish.

“Someone with an anxiety disorder might want to look at their diet and see whether they are getting the recommended daily amount of choline,” Maddock noted, adding that many people in the U.S. do not consume enough. “Some forms of omega-3 fatty acids, like those found in salmon, may be especially good sources for supplying choline to the brain.” This discovery of a consistent chemical signature offers a new window into the biology of anxiety and reinforces the idea that what we eat has a profound connection to how we feel and think.

The study, “Transdiagnostic reduction in cortical choline-containing compounds in anxiety disorders: a 1H-magnetic resonance spectroscopy meta-analysis,” was authored by Richard J. Maddock and Jason Smucny.