A new study by researchers at the University of Bristol has found that the immune system may play a key role in mental health problems like depression, schizophrenia, bipolar disorder, and Alzheimer’s disease.
The study suggests that these conditions may be affected by changes throughout the whole body—not just the brain. This could open the door to new and better treatments for people with mental health issues.
Mental illnesses are common. About one in four people will experience one in their lifetime. However, the reasons why these conditions develop are still not fully understood. Currently, most treatments focus on brain chemicals such as serotonin and dopamine. These are the chemicals that help control mood, sleep, and emotions.
Many antidepressants and antipsychotic medications work by adjusting the levels of these chemicals in the brain. But for about one in three people, these drugs don’t work well. That means there could be other reasons behind these illnesses that are being missed.
In this new study, Dr. Christina Dardani and Professor Golam Khandaker from Bristol’s MRC Integrative Epidemiology Unit used a special method called Mendelian randomization. This technique uses genetic information from large datasets to find out if one thing causes another.
The team focused on 735 proteins related to the immune system—these are the parts of our blood that help fight off infections and respond to inflammation. They looked at whether these proteins were linked to seven different mental health conditions: depression, anxiety, schizophrenia, bipolar disorder, Alzheimer’s disease, autism, and ADHD.
Their analysis showed that 29 immune-related proteins may play a causal role in these mental health problems. Even more promising, 20 of these proteins are already targeted by existing drugs used for other conditions.
This means that scientists might be able to test these drugs for new uses in mental health treatment. It also means we may one day be able to use blood tests to help guide treatment or diagnose certain mental health disorders more accurately.
The results of the study are important because they challenge traditional ideas about mental health. Until now, most experts believed that mental illness is caused by problems in the brain alone—especially with brain chemicals like dopamine or serotonin.
But this research suggests that overactivity in the immune system may also contribute to these problems. In other words, mental illness might be more like a whole-body condition, not just something that happens in the brain.
Professor Khandaker said the findings show that inflammation, both in the brain and in the rest of the body, may increase the risk of developing mental health issues. He explained that this changes the way we should think about mental illness. Instead of seeing the mind and body as separate, we should understand that they are closely connected.
The next step for the research team is to take the proteins they found and study them more closely using other methods. This includes using medical records, running experiments with animals, and carrying out early clinical trials with humans.
These steps will help confirm whether the immune system really causes symptoms and whether changing immune activity can improve mental health.
In summary, this study gives strong evidence that inflammation and the immune system may be important in causing mental health conditions like depression and schizophrenia. While more work is needed, this could lead to new ways to treat and even prevent these illnesses—especially for the many people who do not respond to current medications.
If you care about health, please read studies that scientists find a core feature of depression and this metal in the brain strongly linked to depression.
For more information about health, please see recent studies about drug for mental health that may harm the brain, and results showing this therapy more effective than ketamine in treating severe depression.
The research findings can be found in Molecular Psychiatry.
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