I had just rolled out of bed when I noticed one of my patients, Linda, had texted me several times over the course of the night. Over the past year, she had experienced a profound depression that was starting to interfere with both her work and her marriage. Even though she was reticent to take medication—many of my patients are—she had agreed to a trial run of a selective serotonin reuptake inhibitor (SSRI), Prozac.
When I saw the series of messages, I worried that she was dealing with some uncomfortable side effects of the medicine—or maybe her symptoms were getting worse. It can take four to six weeks for patients to see the effect of the drug. Instead, I saw she had seen news reports of a recent meta-analysis that questioned whether or not the so-called “chemical imbalance” theory of depression—the hypothesis that a lack of serotonin was the cause, at least in part, of depressive and anxiety symptoms—had merit.
Did you see the New York Times? If there’s no proof that there’s a chemical imbalance, why do I need an
SSRI? Is this medication even going to work? What is it actually going to do? There have to be other options, right?
They were valid questions, and she’s certainly not the first person to ask them, even before this sweeping, systematic review of the evidence was undertaken by a group of researchers at University College London. I wasn’t surprised that their findings, which concluded there was “no consistent evidence” of an association between low serotonin levels and depression, were receiving so much attention. And with headlines like “The Study That Changes How We Treat Depression” and “With Chemical Imbalance Theory in Doubt, What’s Next for Depression Care?” filling news and social media feeds across the globe, I wasn’t surprised that Linda, who already had concerns about taking the medication, reached out.
Soon, my inbox was also filling up with more questions—from other patients and a few reporters—asking me what I thought it all meant. And, more importantly, whether it would change the way I continue to treat depression. I spent significant time that week discussing the matter with Linda, as well as many of my other patients.
The truth of the matter is that the idea that low levels of serotonin cause depression has been debated for decades. Every few years, someone questions the efficacy of antidepressant medications or publishes a new study that suggests it’s time to toss out the biological theory of depression. Let’s face it: The idea that the health of our brains—which run on a multitude of hormones, neurotransmitters, proteins, and other neurotrophic factors—comes down to the level of a single molecule is far too simple an explanation. Those of us who study mental health and the brain know that.
Yet, as a practicing psychiatrist, I know that SSRIs, the gold standard for depression treatment, work for many of the patients who come to see me. They have helped save countless lives. How do we square that fact with new evidence that serotonin isn’t the biological mastermind that so many have made it out to be?
The brain is an enigmatic electrical storm made up of the proteins, fats, and vitamins you eat. Each day, as I sit with my patients, its mystery and complexity are readily apparent. It’s high time the medical community, and really everyone, stopped thinking about brain health in terms of one-molecule solutions and started considering mental health conditions like depression, anxiety, attention-deficit hyperactivity disorder (ADHD), and addiction—and the patients living with them—more holistically.
Equally as important, we need to start thinking and talking about mental health beyond diagnosed disorders. Many of the patients I see often don’t exactly meet the diagnostic criteria for depression, anxiety, or any other mental health disorder you will find listed in the Diagnostic and Statistical Manual of Mental Disorders (DSM). But they come to me because they are stressed out, feeling down, overwhelmed, or having difficulty coping with a tough situation. I see more and more of these patients every year. They may not qualify for a specific mental health diagnosis, but they are still struggling. They still need help.
We need a new approach to cultivating mental health. It’s more than past due. Today, more than 50 million Americans live with a mental health concern—and those are just the ones who are willing to admit it. Nearly 5 percent of adults reported having serious thoughts of suicide, leading to 1.6 million suicide attempts in 2021. A startling 20 percent of adolescents experienced a major depressive episode within the last year. The rate of anxiety diagnoses is skyrocketing. And a shocking number of people who meet the criteria for depression, anxiety, or other psychiatric diagnoses go untreated. More and more people who have not received a medical diagnosis are admitting that these days, they just don’t feel quite right.
Even before the latest studies challenging the chemical imbalance hypothesis of depression, experienced mental health professionals understood that these kinds of incidence rates could not be attributed to biology alone. We see that people’s environments also play an important role in how they feel and how they interact with the world around them. The field of epigenetics, or the study of how our environments change how our genes are expressed, means that our DNA is not our health destiny. We have the power to make vital lifestyle changes that can quite literally change the way our bodies read genetic code, determining which genes are expressed and which are silenced. It means that even if you have a family history of mental health disorders, nothing is set in stone. You can counter any genes you have that may put you at risk.
What does this mean in practical terms? It means you can alter your habits in ways that optimize your mental fitness and, consequently, improve your mental health. You no longer have to look at your brain in terms of predestined wiring. You can take targeted actions in your day-to-day life to make your brain more fit and resilient, even in the face of chronic stress. That’s powerful stuff.
The world is changing—and not always for the better. We’ve lived through a cruel pandemic, one that upended our lives in far too many ways. We are tethered to our phones and social media yet feel more isolated and disconnected than ever. We lack true community and purpose. We are experiencing dramatic deficits in nature and engagement—both things known to help our brains thrive. We are stressed to our breaking points, at work and at home. We carry far too much unprocessed trauma—and lack the ability to unburden ourselves.
Our lives are filled with natural and manmade toxins, worming their way into our bodies and brains with every breath we take. And the Western diet, combined with an overly sedentary lifestyle, is robbing our brains of the vital nutrients they need to thrive. We, as a society and as a species, are at a breaking point. Pharmaceutical-only approaches are falling short—and it’s time to look beyond them.
We need to start cultivating mental fitness. And the time to start is now.
This post was excerpted in part from the book Healing the Modern Brain by Drew Ramsey, M.D. Copyright © 2025 by Drew Ramsey, M.D. Reprinted courtesy of Harper, an imprint of HarperCollins Publishers.