The mysteries of the mind

Psychiatric genetics is a new field that adds biology to psychiatry, and it’s revolutionizing our understanding of certain mental illnesses. An interview with Prof. Boris Chaumette, author of a new book on the DNA of schizophrenia.

Dr. Chaumette’s fascination with the mysteries of the human mind was what made him choose psychiatry, and not neurology, as his specialty. The psychiatrist, who is an adjunct professor in the Department of Psychiatry at McGill University and a researcher at the Institut de psychiatrie et neurosciences de  Paris, has been making one discovery after another ever since.  

A picture of Dr. Boris Chaumette
As a psychiatrist with a PhD in neuroscience, Prof. Chaumette explores the genetic and epigenetic bases of psychiatric disorders, especially schizophrenia.
The MD/PhD’s slightly obscure field of study, genetic psychiatry, is revolutionizing our understanding of mental illness. “Traditionally, psychiatrists made their diagnoses based on symptoms a patient expressed, but now we can use biology and genetics to explain certain disorders.” 

The researcher and clinician, who works in Paris at the Hôpital Sainte-Anne—the unofficial name of the GHU Paris Psychiatrie et Neurosciences—just published a new work written for a general audience, Schizophrenie et génétique: un ADN de la folie ? (Schizophrenia and genetics: the DNA of madness?) [HumenSciences, 2024]. Though its title is slightly provocative, this enlightening book explains the latest advances in genetic psychiatry and how these are raising hopes for better treatments.  

“My biggest surprise, as a psychiatrist, is to see how much we are helping families. When I first started studying genetic psychiatry, I was a bit worried that families would reject these new notions. But the opposite is true. Families spontaneously come to us to find out what’s going on.” 

Families have been victims of prejudice for far too long, says Chaumette. “There was a perception that mothers had raised their child badly, or not given them enough affection. Mothers were always blamed, but never fathers. My book says, ‘Schizophrenia is a biological illness, it’s not your fault.’ It takes the guilt off families and friends.” 

Genetic psychiatry will not make gene therapy possible, but it does explain the many forms schizophrenia can take. The field is revolutionizing thinking about psychiatry and sparking controversy, particularly in France, where psychoanalysis has long had a stronghold.

“Psychiatry has always treated the soul in a disembodied way, but genetics tells us that the soul is embedded in matter. Not everyone is open to that.” 

Genetics creates both hopes and illusions about treatment—including a form of determinism that says, “If it’s genetic, nothing can be done about it.” But Chaumette says the opposite is true. “In the case of certain defects in a specific gene, we can say that 50% of people affected will develop schizophrenia. But it’s not an either/or situation. There is no guarantee.” Rather, the information provided by genetics makes it possible to avoid environmental risk factors, such as cannabis use and childhood stress, both major triggers, he explains. This knowledge also offers tools the patient’s support network can use to detect early symptoms. That, in turn, increases the effectiveness of treatment. “Just being informed is liberating.” 

In his book, the researcher shares a telling statistic about the degree of acceptance and resistance to genetic psychiatry. Half the patients in his referral centre come on their own or on the advice of a relative or association. Only 20% are referred by a psychiatrist. “As with AIDS and cancer, it’s the patients, their families and associations that are moving things forward. The people who are most apprehensive about genetic psychiatry are psychiatrists themselves, who are not comfortable with these issues. But I’m hopeful because young people graduating from university today are more aware of the biological factors that cause illness.” 

Dusting off old ideas 

Even if he had chosen another medical specialty, the 39-year-old psychiatrist thinks his personality would have eventually pushed him towards genetics. “Medically and intellectually, it’s absolutely fascinating,” he says. “It’s like detective work, where you use tests and observations to understand things.”  

One of the main reasons Chaumette chose McGill for his postdoctoral studies in 2016–2018 was that research on genetic psychiatry was much more developed here than in his native France. As a member of a team led by Dr. Guy Rouleau, Director of The Neuro (Montreal Neurological Institute-Hospital) and a pioneer in neurogenetics, Chaumette was able to move forward in his work thanks to the availability of data on childhood schizophrenia.  

Born in Évreux, Normandy, Chaumette returned to live in his native country but kept his ties with McGill. “Two or three years ago, I would have told you that my discipline was underdeveloped in France, but the pandemic triggered an epidemic of poorly treated mental illnesses. The French government has been playing catch-up ever since and research budgets are increasing in pace with that.” 

Knowledge about genetic psychiatry is rapidly advancing, but the field is still in its infancy. “We can now provide advice, make recommendations for prevention and adapt care. For certain specific genetic defects, we can establish a fairly precise probability of the disorder occurring. However, when schizophrenia is polygenic, meaning that it involves several genes, genetics can only tell us what is going on in a group of patients. It’s not yet useful for treating individuals.” 

The greatest promise of genetic psychiatry now lies in pharmacogenetics, says the researcher. “Traditionally psychiatrists determine treatment and dosage through trial and error, but that wastes a lot of time. We are starting to be able to use genetics to explain how a patient metabolizes certain drugs. A new strategy called precision psychiatry is emerging, where genetics can be used to establish the best drug and the best dosage for an individual. It’s still in the future, but that’s where we’re headed.” 

Genetic psychiatry has also stirred interest from pharmaceutical companies, who had been losing interest in psychiatry. “We had dopamine treatments that were more or less effective. But research has now identified other neurotransmitters, so we are entering a new phase of therapeutic and clinical trials.” 

When ethics meets genetics 

Chaumette is interested in schizophrenia, in particular, because of what it says about human consciousness.

“Some brain diseases, such as Parkinson’s or multiple sclerosis, are very organic. But schizophrenia combines the purely organic with the human essence, our consciousness. There is something organic going on that modifies consciousness.” 

Even though he has devoted his career to introducing “hard” science into a field considered scientifically “soft,” as he puts it, Chaumette insists that research must not take precedence over psychosocial rehabilitation. “Firstly, genes don’t explain everything. Also, once a person is ill, we need to find the best therapy possible to improve their day-to-day autonomy.”  

For this researcher fascinated by the mind, genetics quickly raises ethical questions. Chaumette believes that marketing genetic tests without professional guidance, a practice carried out in North America, is harmful. The practice is prohibited in Europe, where doubts have been raised about its merits. “Genetic tests are always difficult to interpret. People get so anxious they become sick, and then the test becomes a self-fulfilling prophecy.”  

Chaumette also opposes carrying out systematic screening, for ethical reasons. “What’s the point of screening if there’s no treatment? And what can we do, apart from worry, while we wait for the disease to develop—if it even does develop? Could this be misused by insurers or money lenders? If someone is at risk, should we consider terminating their pregnancy? Given the current state of knowledge, I don’t think large-scale screening is ethical. What is ethical is working to understand why a person develops symptoms in the first place.” 

This article is a translation of the original French, Les mystères de l'esprit.

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