Depression: Why the “Chemical Imbalance” Myth is No Longer Useful

Written by Abeey Yonas

Depression: An Overview

Depression is defined as a mental disorder causing a variety of symptoms, the most common being a general and persistent feeling of sadness. Individuals diagnosed with depression may also experience a change in personality, sleeping and memory difficulties, amotivation, constant fatigue, anxiety, and suicidal thoughts. Around 300 million people globally have depression, making it the most common mental illness in the world.

Since depression was defined, a theory was devised finding the cause of the disorder to be a lack of serotonin in the brain in the ‘60s. Although there has been skepticism surrounding this statement in the scientific community, it has been generally implemented by doctors in the workplace due to the many “studies” conducted proving the cause of depression to be a low level of serotonin. Since then, medications have been developed to attack against a lack of serotonin, such as Selective Serotonin Reuptake Inhibitors (SSRIs) and antidepressants, although some of these treatments were not devised solely based on this theory. Both of these medicines have been used widely to treat depression and improve its symptoms in part due to the extensive marketing and advertising of these medicines to doctors by pharmaceutical companies in the 1990s.

The “Chemical Imbalance” Myth

As discussed, the root of depression has been blamed on a “chemical imbalance” of serotonin in the brain. However, a study done by researchers at University College London published in July of 2022 suggests that there is little to no correlation between depression and low serotonin levels in the brain.

In the study, titled, “The serotonin theory of depression: a systematic umbrella review of the evidence” researchers tested this widely-influential theory by examining studies that deemed depression and its link to serotonin to be correct, a handful of these from one or two decades ago. They then identified six main takeaways from these studies and researched more recent, higher-quality studies testing these same takeaways. The results were irrefutable: in not one of the six takeaways did they find any definite correlation between depression and serotonin. Additionally, any data supporting the correlation theory was denied veracity due to flaws in research processes, such as a small sample size or evidence of low certainty.

What’s the Big Idea?

Since the study’s publication, many psychological journals have reported on the important data making history. The reaction of the scientific community to this news can be described as mixed; while some who were already skeptical of the serotonin theory now have had their suspicions confirmed, others are still not sure about how to take the news and implement it into their practices.

The importance of this new information becoming public knowledge has been heavily stressed, as several studies completed in the duration of the past few decades have been centered around this myth. Since the study, many depressed individuals have questioned whether they should continue taking medicines such as SSRIs and antidepressants; however, as mentioned before, some of these medicines were not created based on this myth and have still been clinically proven to better symptoms of depression, an example of this being through the placebo effect. Dr Joanna Moncrieff, a leader of the study, emphasizes the importance of doctors to continue giving their patients SSRIs and antidepressants, and to only halt these medications gradually and with care.

Sources

https://www.independent.co.uk/news/world/americas/depression-serotonin-levels-antidepressants-pills-side-effects-b2135378.html

https://www.theguardian.com/commentisfree/2022/aug/03/the-chemical-imbalance-theory-of-depression-is-dead-but-that-doesnt-mean-antidepressants-dont-work

https://slate.com/technology/2022/08/ssris-chemical-imbalance-depression.html

https://www.nature.com/articles/s41380-022-01661-0

https://www.mayoclinic.org/diseases-conditions/depression/symptoms-causes/syc-20356007

https://www.everydayhealth.com/serotonin/guide