MADRID.− There are very close genetic connections between some psychiatric illnesses. It will be seen in the clinic when Doctors find it difficult to label a specific disease or, for example, they discover that a patient with depression also develops anxiety. The boundaries between some mental illnesses and others are sometimes confusing at the consultation level, and this has an explanation at the molecular level: There is a kind of “genetic relationship”, common risk variants between diseases.
A new study published Wednesday, the 10th of this month, in the journal Nature And based on DNA analyzes from more than a million peoplehas delved into this area and illuminated the molecular thread that connects fifteen mental disorders.
Special, This international research has found that 14 diseases are common more or less strong genetic risk variants. These are molecular signals that predispose the development of these mental states. The authors explicitly pointed this out five groups of diseases that have a high genetic correlation: occurs, for example, between schizophrenia and bipolar disorder; or between anxiety, depression and post-traumatic stress; or between autism and attention deficit hyperactivity disorder (ADHD).
The results suggest that common genetic traits are closely linked to the early stages of brain development. An in-depth study of these characteristics could help better understand mental disorders, improve diagnosis, and promote new treatments.
This research follows other studies that have already shed light on fragments of these genetic connections between brain diseases in recent years. “It’s about unraveling all the pieces of the genetic puzzle to create precise and predictive medicine.“ explains Antoni Ramos Quiroga, head of psychiatry at the Vall d’Hebron Hospital in Barcelona and researcher at the Biomedical Research Center of the Mental Health Network (Cibersam).
The doctor involved in this and other research in the same field assures that studies like this “will help redefine mental disordersnot just based on symptoms, but also based on genetic variables.”
In this case the authors five categories identified that link groups of mental illnesses with high levels of shared genetic risk. So that’s it “force factor” It includes anorexia nervosa, obsessive-compulsive disorder (OCD) and Tourette syndrome in the same group.
The call “Internalization factor” It combines depression, anxiety and post-traumatic stress. Another category is that of Tandem schizophrenia and bipolar disorder. He “Neurodevelopment factor” thinks about autism and ADHD. And the final category with strong genetic similarities is that of Substances of abusewhere tobacco, alcohol, cannabis and opioid addictions are grouped together. The strongest correlation appears within each group, but also There are common genetic signals between complaints in different categories.
“For example, between ADHD and depression “There is a high percentage (of common genetic variants),” illustrates Ramos Quiroga. He emphasizes that the results are consistent with the “clinical reality” observed in the consultation.
These common genetic signals, Ramos Quiroga clarifies, are “predisposing factors”. That means they increase the risk. However, remember that the presence of any of these variables does not mean that a person will develop one of these diseases.
Many genes, but also the environment, influence the development of mental disorders. There is “an interaction between factors,” recalls the psychiatrist from Vall d’Hebron: “There are factors of origin that predispose us“But we also need to focus on the environment and, for example, fight against sexual assault or drug abuse (these conditions increase the risk of deteriorating mental health).”
The authors of the article published in Nature They assume that the identified risk variants play a role in the early stages of brain development. “That tells us that These genetic factors determine how the neural connection develops in the brain. and there can be a change right from the start,” reflects Ramos Quiroga.
In an accompanying commentary, Abdel Abdellaoui, researcher at the Department of Psychiatry at the University of Amsterdam, also emphasizes: “In all factors associated genes show their maximum expression during fetal developmenthighlighting the importance of early developmental processes in psychiatric risk.”
However, Ramos Quiroga asks not to lose sight of the complexity of these disorders and recalls that they are multifactorial: “If you have a vulnerability and add other factors that increase that vulnerability, it is worse: There are genetic factors that pose a higher risk and they have to do with how the brain develops, but there are also other variables related to immunological factors; and beyond The environment also has an influence Because if it causes stress, for example, it affects the immune system,” he emphasizes.
Abdellaoui agrees, pointing out that these psychiatric disorders appear to occur when “Certain combinations of genes and life experiences combine unfavorably”. “This should redefine mental illness not as a flawed biology, but as an unfortunate intersection between natural variation and environmental stress,” he argues.
Abdellaoui, on the other hand, claims that these genetic variants are divided into five categories “that go beyond current diagnostic boundaries” and wonders whether these genetic patterns, common to 14 psychiatric disorders, may lead us to rethink the diagnostic framework of mental illnesses.
“Only a few genetic variants can be traced back exclusively to a single diagnosis“Suggesting that the Diagnostic and Statistical Manual (DSM; the traditional tool for diagnosing psychiatric disorders) categories may be clinically useful, but appear to be arbitrary at the biological level,” he agrees.
Francina Fonseca, head of psychiatry at the Hospital del Mar in Barcelona, defends this Current classifications continue to be useful because they help professionals understand each other and speak the same language.. However, he assumes that we must “be self-critical, humble and strict” and try to continually refine the diagnoses.
The psychiatrist clarifies that this research, in which she was not involved, will not have an immediate impact on clinical practice, but will help to better classify these diseases: “In the mental health field, there are no laboratory or imaging tests that allow us to diagnose what is happening in the brain.. We focus on symptoms that are based on or able to interpret the subjectivity of the person suffering. But to achieve a good diagnostic and therapeutic approach, We have to find the physiological changewhich circuits in the brain are changed.”
Ramos Quiroga agrees that this entire line of research “will contribute to achieving a classification of mental disorders more closely linked to biological factors,” adding It also opens the door to identifying molecular targets on which new drugs can be developed..
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