The genetic link between the results of blood and mental tests…

The Research It will increase our understanding of what causes mental illness and may help identify new treatments.

the perfect mind in healthy body

People often consider mental health to be separate from the health of the rest of the body. This could not be further from the truth: there is clear evidence that many biochemicals are involved in diseases such as diabetic And autoimmune conditions It directly affects the function of our brain.

Several studies have attempted to address this by focusing on substances called biomarkers that can be easily measured in the blood.

A biomarker is simply something in the body that is a sign of a particular disease or process. These things often have to do with the type of things reported in the blood test your doctor orders, such as cholesterol, blood sugar, liver enzymes, vitamins, or inflammatory markers.

Biomarkers found in routine blood tests are useful because they are often affected by diet and lifestyle, or by treatment with one of the medications.

The complex role of genetics in mental health

It is often difficult to study the role of these blood biomarkers in mental health conditions. Often many studies in this area are not large enough to draw strong conclusions.

One solution is to look at genetic influences on both mental illness and the substances measured in the blood. Genetics is useful because we now have data from millions of individuals who have volunteered for research studies.

Both mental illness and blood biomarkers are what geneticists callcomplex featuresIn complex traits, many genes are involved and environmental factors also contribute.

The wide availability of genetic data has allowed us to investigate the extent to which large numbers of small changes in DNA sequence (or ‘variants’) are associated with the risk of mental illness. These same variables can also be linked to the measured levels of a vital sign in the blood.

For example, a variant in a particular gene may increase the risk of developing schizophrenia and also be associated with low levels of the vitamin in the blood. Most of these variables are individually associated with very small changes in something like risk of developing mental illness, but they may add up together to produce larger effects.

How are blood biomarkers related to mental illness?

Our recent study sought to use genetics to investigate the relationship between nine psychiatric disorders and 50 factors measured in routine blood tests, such as cholesterol, vitamins, enzymes, and indicators of inflammation. We used data from very large studies conducted by other people, with data from nearly 1 million volunteers included in the total.

Our study first confirmed the existence of the so-called genetic link among blood biomarkers and mental illness, which were more prevalent than previously demonstrated. Genetic association means the effect of DNA sequence changes on mental illness risk and the levels of a particular biomarker were more similar to each other than might have occurred by chance alone.

To take one example, there was a positive genetic association in our study between white blood cell count and depression. This may indicate that some processes in our body affect both depression and white blood cells.

If we can identify what this common process is, it may lead to a better understanding of what causes depression and treatment can be targeted.

Correlation verses causal

Our study showed that there was Relationship between mental illness genes and blood factors, but this does not tell us whether blood biomarkers are involved in what the reasons mental illness.

To distinguish correlation from causation in medicine, the gold standard approach is to conduct clinical trials in which patients randomly receive either a treatment or a placebo. However, these experiments are expensive and difficult to perform.

We did the next best thing: use DNA variants associated with changes in blood biomarkers to serve as a Natural Clinical Experience. This process takes advantage of the fact that we randomly inherit DNA variants from our parents, in the same way that participants in clinical trials receive a treatment or a placebo at random.

It is a complex method and the results need careful interpretation.

We found evidence that some of the substances measured in the blood may actually be involved in the cause of some mental illnesses. Proteins related to the immune system, for example, may be involved in depression, schizophrenia, and anorexia.

More work is now needed to determine exactly how these blood measures are involved in these disorders, and to see if they can be targeted for treatment. DM / ML

This story was first published in Conversation

William Reay is a Postdoctoral Research Fellow in the School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, New South Wales, Australia, University of Newcastle.

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