From Mad in America: After many years of believing that low serotonin in the brain causes depression, a new review has shown that this theory is not supported by evidence.
The chemical imbalance theory, which says that low serotonin leads to depression, first came out in the 1960s. In the 1990s, the pharmaceutical industry spread this idea to the public, which led to antidepressants becoming common among the public. These medicines target serotonin, which is a neurotransmitter (a type of brain chemical). However, recent research has debunked this theory.
In a big review of research on serotonin and depression, researchers found no clear link between serotonin levels and depression. They looked at various aspects, such as plasma serotonin levels, serotonin receptor activity, serotonin depletion experiments, and serotonin genetics. In other words, they looked thoroughly to find any connection between different types of serotonin activity and depression. Despite a lot of research efforts, there was no good evidence supporting the serotonin theory of depression. The researchers write,
“Whereas some earlier, lower quality, mostly smaller studies produced marginally positive findings, these were not confirmed in better-conducted, larger and more recent studies.”
The researchers, led by Joanna Moncrieff at University College London, said that we need to carefully re-study the evidence on serotonin and depression. They concluded that it’s time to recognize that the serotonin theory of depression lacks solid scientific backing.
This study is the first of its kind to examine all the evidence in a systematic manner. While the chemical imbalance theory has been widely promoted for years, experts in the field of psychiatry have criticized it for lacking strong scientific support.
Belief in the chemical imbalance theory can have negative results for those suffering. People may develop a pessimistic view of depression, feeling that they have no control over their moods due to their brain chemistry. This may discourage them from finding other types of help like therapy, or from making meaningful changes in their lives. They might only focus on antidepressant medicines which have a lot of serious side-effects. Often patients are not informed about the side effects or about the fact that these medicines can be addictive. Recently, the UK’s leading body National Institute of Care and Excellence changed their guidelines to reflect that antidepressants can be very addictive, and now give resources to people so they can safely stop this medicine.
Unfortunately, for most people, antidepressants don’t work effectively. Studies have shown that less than 25% of patients improve with treatment, including multiple antidepressants. Many people who don’t experience any benefit from the medicine are still hesitant to stop using them because they fear their depression could worsen without the impact of the drugs on serotonin levels.
As a result, of many people taking antidepressants, at least 75%, may have long-term side-effects of these drugs, such as weight gain, sexual dysfunction, and emotional numbness, without having any improvement in their depression.
Senior author Mark Horowitz emphasized the need for honesty and transparency with patients. While antidepressants may help manage some symptoms, they are not a complete solution or cure for depression based on the evidence available.
This article originally appeared in Mad in America and can be read here.
This is an AI generated version shortened and edited for a South Asian audience.