Camilla Nord, neuroscientist: “Sadness is normal, but depression is debilitating.”

Camilla Nord (Paris, 36) directs the Mental Health Laboratory at the University of Cambridge, where she is a professor of cognitive neuroscience. With a certain resemblance to a grown-up Hermione Granger, she greets us between classes in a glass-walled office overlooking a garden where squirrels play. Born in France and raised in Washington, D.C., the daughter of an American father and a Dutch mother, as evidenced by an accent difficult to pinpoint. In an essay published this year, *The Brain in Balance * (Paidós), she argues three points: that there is no single cure for depression, that medications are not as harmful as many claim, and that the nervous system strives for stability throughout life, a stability that, unfortunately, will always be precarious.

Q. This morning at Tate Britain I saw a painting by Ithell Colquhoun entitled Depression : A Bundle of Threads, Tight and Tangled. Does it ring a bell?

R. It tells me a lot. It describes the cage of depression: the feeling of not being able to escape. But that door can be opened. There are always ways out, even if they aren't the same for everyone.

Q. Unlike other experts, you don't choose sides: you accept multiple treatments and consider them all valid.

A. A single treatment doesn't work for everyone. Research shows the opposite: disorders are diverse, the causes are multiple, and therefore, there must be several ways to treat them. We scientists have already passed that stage. Now it's time to explain it better to the public.

Q. Some people use depression as a synonym for sadness. How do you refute that?

A. Depression is a profound alteration of emotional, and to some extent physical, experience that impairs our vital functions. It's important to distinguish between normal variations in mental health—because we don't always have to be happy—and the illness itself, which requires treatment to restore those functions. Feeling sad is normal, but depression is debilitating.

Q. There is a lot of mistrust about the relationship between scientists and the pharmaceutical industry .

R. It's a legitimate concern, stemming from biases, the concealment of adverse outcomes, and the unfair promotion of certain drugs. I don't collaborate with the industry, although I am aware of solid studies funded by pharmaceutical companies. Drugs shouldn't be excluded, but neither should they become the only option. Biology is also modified by experiences and habits.

P. He argues that drinking coffee in the sun or laughing at a movie can act on the brain in a way comparable to a drug.

R. Our experiences change how our brains function. There are wonderful studies: watching a comedy with friends activates the endogenous opioid system and raises the pain threshold. Its effect is similar, on a smaller scale, to that of an analgesic. It shows that there can be common biological roots through different pathways: the pharmacological, of course, but also the experiential.

Q. Spain is among the European countries with the highest number of mental health diagnoses. Why do some countries have more depression than others?

R. There are significant geographical and temporal variations. Part of this is explained by access to care: greater access always leads to more diagnoses. But even with equal access, environmental factors—poverty, perhaps pollution—, small genetic differences, and, above all, the different cultural expressions of emotions all play a role. Each culture expresses distress in different ways, and this also affects psychiatric disorders. Stigma also plays a significant part: where there is more shame, there are always fewer diagnoses.

Q. Are we more depressed today, or do we just talk about it more?

A: There's no definitive answer. Part of the visible increase in cases is due to this improved access. But there are also signs of a slight decline in well-being, especially among young people. Greater awareness of the problem has a downside: it encourages monitoring symptoms and attributing them to clinical factors, when sometimes they are simply the normal ups and downs of life. Furthermore, the state of the world plays a role. The pandemic damaged mental health, and we also see this with the climate crisis or the threat of war, particularly among young people, although this needs to be confirmed at a population level.

Q. You study the balance of the nervous system. What is a stable brain and how is it achieved?

R. The brain is constantly readjusting. It's a predictive organ that aligns lived experiences and expectations with the environment to maintain homeostasis, the body's ability to maintain stable internal conditions despite external changes. We don't achieve brain equilibrium once and for all. We are obliged to readjust it throughout our lives.

Q. Electroshock therapy has a bad reputation. You say that, unfortunately, it works.

R. I hesitated to include electroconvulsive therapy in my book because of its dark history, but the data shows great effectiveness in treating very severe depression. The problem lies in the side effects, especially on memory. Even so, the models don't point to brain damage, and cell growth has even been observed in specific areas. But if someone is experiencing memory loss, it must be taken very seriously. That's why it's reserved for cases where no other solution has worked, always with informed consent and close monitoring.

Q. The hypothesis that drugs compensate for a serotonin deficiency has been discredited, yet you maintain that antidepressants work in about half of patients. How do you explain this?

R. During the second half of the 20th century, there was deceptive marketing: it was touted as correcting this supposed deficiency without sufficient evidence, and the adverse effects were minimized. Even so, this medication works for many people, without a clear explanation. I wouldn't rule it out, but not because it corrects a supposed deficiency, but because it alters how we process the ambiguity of some emotions, which we can decode as good or bad.

Q. How do antidepressants work if they don't correct a deficit?

R. By changing serotonin levels—without the need for a prior deficiency—they alter the processing of emotional signals and shift us toward a more neutral or positive position. They don't instantly raise our mood, but rather adjust the bias with which we interpret these ambiguous interactions and signals. It's like changing the filter through which you see.

“Excluding medication is not the solution. There are people who, after trying everything, climb out of the abyss with a drug. They must have access to it.”

Q. What is your response to those who oppose overmedication and rapid diagnoses?

R. I understand: with such overwhelmed healthcare systems, prescribing medication is more immediate than offering psychotherapy , which requires time and resources. I, too, would prefer more personalized decisions, but excluding medication isn't the solution. There are people who, after trying everything, find their way out of despair with medication. I believe they should have access to it.

P. He dedicates the book to his daughter and wife, and opens it with a scene from his wedding. Why expose himself so much, something many scientists avoid?

R. In my scientific articles, I never talk about myself. In the book, I also wanted to open up the world of those of us who do science: why we think what we think, where our vocation comes from, and when we change our minds. If I wanted to teach people to see the world as scientists, I had to show them a little bit about who they are looking at.

Q. Have you suffered from depression?

R. Not me, but very close people have. Perhaps that's why I'm obsessed with understanding it. A leading figure in the field, Nolan Williams, recently committed suicide. It was devastating. That reminds us that, however close we are to scientific solutions, nothing is ever enough to deal with depression.

Q. Would you have been a better scientist if you had been depressed?

R. I would be a worse scientist if I didn't work side by side with those who have lived through it or if I didn't listen to them.

Q. And the last one: I hear she's a big fan of Buffy the Vampire Slayer . Did that influence her?

R. For me, it's an ethical model: doing the right thing and thinking about the common good, even when it doesn't benefit you personally. In academia, you can advance at the expense of others. Leading a lab means receiving credit for work that is always a collective effort. I try never to put myself before the team. You can be both a successful and compassionate person.