Largest Genetic Map of Psychiatric Disorders So Far

Approximately 20% of the world population is affected by some type of psychiatric disease that can alter intellectual ability, behavior, emotions, and social relations. (Update on most current statistics according to NIMH)

Stop and just think about that for a minute.  20%, one fifth of our world’s population, is affected by a a mental health disorder.  Even if you are not the one out of every five, odds are you either have a family member or close friend who is that one out of five. So, 1 in every 5 at your office function, church dinner, or neighborhood block party.  The scenarios go on and on. You get the picture. 

In this blog, I’m going to share an article on the largest genetic map of psychiatric disorders we have so far.  I encourage you to read the article, in its entirety.  The link is at the end of this blog.  Summing up:

In the largest international study published so far on the genetics of psychiatric disorders, which has been promoted by the Psychiatric Genomics Consortium, researchers analyzed the genetic base shared by eight psychiatric disorders:

  • anorexia nervosa, obsessive-compulsive disorder, bipolar disorder, major depressive disorder, schizophrenia, autism spectrum disorder, ADHD, and Tourette Syndrome

The study further defines three groups from within these eight disorders that are highly genetically related to each other. They are:

  • Compulsive Behaviors                   (anorexia nervosa, obsessive-compulsive disorder)
  • Mood and Psychotic Disorders      (bipolar disorder, major depressive disorder, schizophrenia
  • Early-Onset Neurodevelopmental Disorders   (autism spectrum disorder, ADHD, Tourette Syndrome)

“This study, consisting of 230,000 patients and 500,000 controls, does not put emphasis on the genes shared by members of a particular group.  Rather, on the genes shared by the highest number of disorders”, notes Bru Cormand, professor at the Department of Genetics, Microbiology and Statistics and head of the Neurogenetics Research Group at the UB.  “That is, those factors that would somehow give way to a ‘sensitive’ brain, more likely to suffer from a psychiatric disorder. And the fact that this could be one or another disorder would depend on specific genetic factors, not forgetting about the environmental factors”.

Many psychiatric disorders show co-morbidities, they tend to co-occur, sometimes in a sequential manner. Therefore, it is quite likely for a patient to show more than one disorder over their life.

The results indicated that a gene related to the development of the nervous system – DCC – is a risk factor for all eight disorders, and RBFOX1 is involved in seven out of the eight disorders.  Further findings included that ADHD and depression share 44% of those genetic risk factors that are common in the general population. Regarding schizophrenia and bipolar disorder, these figures reach 70%. According to the expert Antoni Ramos-Quiroga, “these results help people with ADHD so they can understand the disorder and also why they can suffer from depression more frequently. Furthermore, this is new scientific evidence that ADHD can persist over life, and be present in adults. We hope this helps to reduce the social stigma regarding ADHD and the other mental illnesses”.

The study further looks into the expression of risk factors in psychiatric disorders. One of the most relevant findings of the study reveals that those genes that are risk factors for more than one disorder –genes with pleiotropic effects- are usually active during the second trimester of pregnancy, coinciding with a crucial stage in the development of the nervous system.  However, it’s important to note that some genetic variations can act as risk factors in a certain disorder, but have a protective effect in other cases.

As for hereditary genetics versus environmental factors, psychiatric disorders have a multifactorial origin.  For instance, ADHD has a 75% genetic load, and the remaining 25% would be explained by environmental factors.  This data was derived from twin studies.  Other psychiatric disorders in the study could be viewed in the same way because the contribution of genetics is generally over 50%.

In the future, one of the priorities of the Consortium will be to complete the genetic landscape of mental disorders through the analysis of other genetic variations. From an epigenetic perspective –in particular the methylation of DNA- the Consortium wants to analyze the interactions between genes and environment, which could be decisive in psychiatry.

“It will be important to understand how genetic alterations are translated to the actual disorders (phenotypes), and this involves studying the function of every single gene identified in the genomic studies. Bru Cormand and Raquel Rabionet note, “The objective is to use genetics to improve and customize the diagnosis, prognosis and therapy of these pathologies which may be highly disabling for the affected people.”

Please let your voice be heard in order to increase funding for much needed genetic research. Contact your legislators. See our ‘Contact Your Legislators’ page for help in contacting your own particular representatives and senators. Thank you!

Remember to support our “Moonshot for Mental Health” initiative.