In a recent paper published in Molecular Psychiatry, author Joanna Moncrieff debunks the age-old hypothesis that depression is caused by a chemical imbalance in the brain. Moncrieff and colleagues performed a meta-analysis looking at all the major studies on this hypothesis and found that none of them showed a connection between serotonin levels and depression. On the contrary, the authors found that long-term use of anti-depressants reduced serotonin levels!
The idea that low serotonin in the brain causes depression was first promulgated in the 1960’s, with no evidence to back it up. It is estimated that about 80% of the public believes that this hypothesis is true.
The author’s conclusion:
The main areas of serotonin research provide no consistent evidence of there being an association between serotonin and depression, and no support for the hypothesis that depression is caused by lowered serotonin activity or concentrations… We suggest it is time to acknowledge that the serotonin theory of depression is not empirically substantiated.Joanna Moncrieff
It has been known for several decades that the hypothesis that depression is caused by a chemical imbalance was not true. It seems to take a long time for the research to trickle down to the average person. I don’t see mainstream opinions changing anytime soon. It is too useful to believe that life problems are caused by chemicals in the brain rather than the result of struggling with the vicissitudes of life, or dealing with personal challenges.
I spoke with Irving Kirsch on my podcast several years ago about some of these ideas in his book, The Emperor’s New Drugs: Exploding the Antidepressant Myth, which you can listen to below.
The chemical imbalance myth is similar to the idea that something called addiction causes a person to drink or use drugs. This won’t seem to go away either, despite decades of research that has shown that addicts can control their behavior when incentivized to do so. Yet, the idea that inert chemicals can cause a person to behave irresponsibly persists. Jeffrey Schaler wrote about how Addiction is a Choice in his book by that title, Herbert Fingaret debunked the idea that alcoholism is a disease in his book Heavy Drinking, and William Playfair took on addiction from a religious perspective in The Useful Lie.
Thomas Szasz pointed out that how we live life, and the choices we make, ultimately depend on the person we chose to be:
When and why do we say that a behavior is caused rather than willed?
We say that chemicals in the brain cause depression and suicide; but we don’t say that chemicals in the ovaries or testicles cause lust and marriage.
Chemicals in our bodies incline us toward certain behaviors. Inclinations give us options, to engage in or abstain from certain behaviors. Absent hunger or lust, there is no temptation to eat or copulate. Absent depression (or disability, old age, etc.), there is no temptation to kill oneself.
Self-discipline enables us to choose whether to yield to or resist particular inclinations. Our choices determine what we do and who we are.Szasz, Thomas. Words to the Wise (p. 11). Taylor and Francis. Kindle Edition.