There are admittedly probably a few people with actual chemical imbalances in the brain that cause depression, but for the most part, I think the commonly false chemical imbalance narrative is a ploy pushed by pharmaceutical companies to make profits. I lived years of my life with pretty severe depression and I knew that antidepressants wouldn’t remedy that — if anything, they would have made it worse. I learned that sleeping enough, exercising fairly often, finding some satisfying sex life (ideally finding a lover), limiting or avoiding drug intake, having a healthy diet, having good friends, and doing work that is fulfilling and meaningful are much better types of solutions than relying on a pill. The underlying problem has to be fixed for real happiness — it shouldn’t be artificially made with drugs.
Some 2,000 years ago, the Ancient Greek scholar Hippocrates argued that all ailments, including mental illnesses such as melancholia, could be explained by imbalances in the four bodily fluids, or “humors.” Today, most of us like to think we know better: Depression—our term for melancholia—is caused by an imbalance, sure, but a chemical imbalance, in the brain.
This explanation, widely cited as empirical truth, is false. It was once a tentatively-posed hypothesis in the sciences, but no evidence for it has been found, and so it has been discarded by physicians and researchers. Yet the idea of chemical imbalances has remained stubbornly embedded in the public understanding of depression.
Prozac, approved by the US Food and Drug Administration 30 years ago today, on Dec. 29, 1987, marked the first in a wave of widely prescribed antidepressants that built on and capitalized off this theory. No wonder: Taking a drug to tweak the biological chemical imbalances in the brain makes intuitive sense. But depression isn’t caused by a chemical imbalance, we don’t know how Prozac works, and we don’t even know for sure if it’s an effective treatment for the majority of people with depression.
One reason the theory of chemical imbalances won’t die is that it fits in with psychiatry’s attempt, over the past half century, to portray depression as a disease of the brain, instead of an illness of the mind. This narrative, which depicts depression as a biological condition that afflicts the material substance of the body, much like cancer, divorces depression from the self. It also casts aside the social factors that contribute to depression, such as isolation, poverty, or tragic events, as secondary concerns. Non-pharmaceutical treatments, such as therapy and exercise, often play second fiddle to drugs.
In the three decades since Prozac went on the market, antidepressants have propagated, which has further fed into the myths and false narratives we tell about mental illnesses. In that time, these trends have shifted not just our understanding, but our actual experiences of depression.
Both the narrative and the use of drugs to treat symptoms of depression transformed after Prozac—the brand name for fluoxetine—was released. “Prozac was unique when it came out in terms of side effects compared to the antidepressants available at the time (tricyclic antidepressants and monoamine oxidase inhibitors),” Anthony Rothschild, psychiatry professor at the University of Massachusetts Medical School, writes in an email. “It was the first of the newer antidepressants with less side effects.”
Even the minimum therapeutic dose of commonly prescribed tricyclics like amitriptyline (Elavil) could cause intolerable side effects, says Hyman. “Also these drugs were potentially lethal in overdose, which terrified prescribers.” The market for early antidepressants, as a result, was small.
Prozac changed everything. It was the first major success in the selective serotonin reuptake inhibitor (SSRI) class of drugs, designed to target serotonin, a neurotransmitter. It was followed by many more SSRIs, which came to dominate the antidepressant market. The variety affords choice, which means that anyone who experiences a problematic side effect from one drug can simply opt for another. (Each antidepressant causes variable and unpredictable side effects in some patients. Deciding which antidepressant to prescribe to which patient has been described as a “flip of a coin.”)
Rothschild notes that all existing antidepressant have similar efficacy. “No drug today is more efficacious that the very first antidepressants such as the tricyclic imipramine,” agrees Hyman. Three decades since Prozac arrived, there are many more antidepressant options, but no improvement in efficacy of treatment.
Meanwhile, as Lacasse and Leo note in a 2005 paper, manufacturers typically marketed these drugs with references to chemical imbalances in the brain. For example, a 2001 television ad for sertraline (another SSRI) said, “While the causes are unknown, depression may be related to an imbalance of natural chemicals between nerve cells in the brain. Prescription Zoloft works to correct this imbalance.”
Another advertisement, this one in 2005, for the drug paroxetine, said, “With continued treatment, Paxil can help restore the balance of serotonin,” a neurotransmitter.
“[T]he serotonin hypothesis is typically presented as a collective scientific belief,” write Lacasse and Leo, though, as they note: “There is not a single peer-reviewed article that can be accurately cited to directly support claims of serotonin deficiency in any mental disorder, while there are many articles that present counterevidence.”
Despite the lack of evidence, the theory has saturated society. In their 2007 paper, Lacasse and Leo point to dozens of articles in mainstream publications that refer to chemical imbalances as the unquestioned cause of depression. One New York Times article on Joseph Schildkraut, the psychiatrist who first put forward the theory in 1965, states that his hypothesis “proved to be right.” When Lacasse and Leo asked the reporter for evidence to support this unfounded claim, they did not get a response. A decade on, there are still dozens of articles published every month in which depression is unquestionably described as the result of a chemical imbalance, and many people explain their own symptoms by referring to the myth.
Meanwhile, 30 years after Prozac was released, rates of depression are higher than ever.
Depression is now a global health epidemic, affecting one in four people worldwide. Treating it as an individual medical disorder, primarily with drugs, and failing to consider the environmental factors that underlie the epidemic—such as isolation and poverty, bereavement, job loss, long-term unemployment, and sexual abuse—is comparable to asking citizens to live in a smog-ridden city and using medication to treat the diseases that result instead of regulating pollution.
Investing in substantive societal changes could help prevent the onset of widespread mental illness; we could attempt to prevent the depressive health epidemic, rather than treating it once it’s already prevalent. The conditions that engender a higher quality of life—safe and affordable housing, counsellors in schools, meaningful employment, strong local communities to combat loneliness—are not necessarily easy or cheap to create. But all would lead to a population that has fewer mental health issues, and would be, ultimately, far more productive for society.