Episode 2: Depression and the Chemical Imbalance Theory
In the previous article, I discussed the relationship between tax policy, economic conditions, and mental health. That connection will remain a central focus going forward, as it is the primary reason I began this series. Before going deeper into economics, however, it is important to address a widespread misconception about depression.
For roughly the past forty years, most people—both inside and outside the mental health field—have been told that depression is caused by a chemical imbalance in the brain. Surveys suggest that more than 80 percent of people in the United States believe this to be true. The problem is that it is not true. On closer inspection, it is not even a plausible hypothesis.
Rates of depression have tripled over the past 25 years. That kind of change does not resemble a biological or genetic phenomenon. Human genetics do not shift on that timescale. The idea that a sudden chemical malfunction has emerged across an entire population simply does not hold up.
There are two primary reasons this belief persists.
The first is pharmaceutical marketing. Drug companies have spent billions of dollars over decades promoting the idea that depression is caused by a chemical imbalance. If depression can be framed as a biological defect, it can be treated as a pharmaceutical problem. This messaging has been extremely effective. Prozac, the most well-known antidepressant, generates more than two billion dollars in annual profit.
What is far less effective, according to large meta-analyses, are antidepressants themselves. For approximately 85 percent of people who take them, antidepressants do not perform better than a placebo. In addition, roughly 70 percent of users experience side effects such as emotional blunting, sexual dysfunction, and, paradoxically, suicidal thoughts. For many individuals, the costs outweigh the benefits. Despite this, antidepressants continue to be widely prescribed and aggressively marketed.
The second reason the chemical imbalance myth persists is motivated reasoning. People are more likely to accept explanations that are comforting or that offer a sense of control. A chemical or genetic explanation allows depression to be seen as something impersonal and unavoidable. If depression is caused by brain chemistry, then no deeper questions need to be asked.
The alternative is much more uncomfortable. It suggests that depression may be a response to the way people are living, the choices they are constrained to make, or the environments they inhabit. Accepting that explanation implies that meaningful change is required, not just at an individual level, but at a collective one.
There are two related misconceptions worth briefly addressing. One is the idea that serotonin plays a central role in depression. It does not. The other is the belief that depression is a genetic disorder. It is not. Research suggests that genetics account for roughly 10 percent of depression risk.
If depression is not caused by chemical imbalances and is only minimally influenced by genetics, then approximately 90 percent of depression must be attributable to individual circumstances and environmental conditions. Once again, consider the fact that depression rates have tripled in just 25 years. Either human brain function has changed at a rate never before seen in evolutionary history, or the environment has changed. The latter explanation is the only reasonable one.
In the previous article, I argued that collapsing living standards are the primary driver of rising depression rates. I also examined the financial realities facing young adults in the United States to illustrate how unsustainable those conditions have become.
The data support this conclusion. A 2021 study from the Substance Abuse and Mental Health Services Administration tracked rates of mental illness by age group over time. Among adults aged 50 and older, rates remained essentially unchanged between 2008 and 2021, hovering around 15 percent. For adults in their late twenties through forties, rates increased from roughly 21 percent to about 28 percent over the same period. Among the youngest group, ages 18 to 25, rates rose from approximately 18 percent in 2008 to 34 percent in 2021.
In other words, rates of mental illness among older adults have remained stable, while rates among younger adults have nearly doubled.
This pattern is not random. It indicates that the forces driving the mental health crisis are disproportionately affecting younger generations. The reason is economic. Adults over 50 are largely insulated from many of the pressures reshaping the economy. Many have already purchased homes, raised families, and accumulated retirement savings. They benefit from Social Security, have access to Medicare, and often hold pensions, investments, or other assets built during a more stable economic era.
Younger adults do not share those advantages. They face housing markets they cannot afford, student debt that delays or prevents financial stability, and shrinking access to healthcare and social programs. They are told that Social Security may not exist when they retire, despite being required to continue paying into it. They are increasingly aware that their standard of living will likely be lower than that of their parents.
These are not personal failures or psychological defects. They are rational responses to deteriorating conditions.
The rise in depression is not genetic. It is not chemical. It is economic.
With that foundation established, we can move on to connect tax policy, wealth concentration, and the modern depression epidemic. We will pick up here next time.
References:
1 - https://journals.sagepub.com/doi/abs/10.1177/0022146512471197
2 - https://www.bmj.com/content/bmj/378/bmj-2021-067606.full.pdf
3 - https://www.nature.com/articles/s41380-022-01661-0
4 - https://pmc.ncbi.nlm.nih.gov/articles/PMC5934326/pdf/nihms943355.pdf