The chemistry of depression is not really known.

Depression is probably not caused by a chemical imbalance in the brain, according to a study published in the journal Molecular Psychiatry.

For three decades, psychiatrists have insisted that depression is caused by a chemical imbalance in the brain, specifically, by a deficiency of the neurotransmitter serotonin. However, this theory has no scientific backing.

The serotonin theory has been supported by the pharmaceutical industry

Although first proposed in the 1960s, the serotonin-depression theory began to be widely promoted by the pharmaceutical industry in the 1990s in association with its efforts to market a new range of antidepressants, known as selective serotonin reuptake inhibitors or SSRIs.

The idea was also supported by official institutions such as the American Psychiatric Association, which still maintains today that “differences in certain chemicals in the brain can contribute to symptoms of depression.”

Countless doctors have repeated the message around the world, in their private offices and in the media. Patients with depression have been taking antidepressants to correct a suspected chemical imbalance in the brain that was causing their depression.

However, for a long time there have also been scientists who have drawn attention to the lack of evidence to support the idea that depression is the result of abnormally low or inactive serotonin.

It is true that taking antidepressant medications can improve symptoms (although they are only slightly more effective than placebos), but this does not confirm that the cause of depression is related to serotonin. There are other explanations for the effects of antidepressants. These medicines flatten or numb emotions, which influences the evolution of mood.

There is no evidence of an imbalance in serotonin

Researchers from several European universities have carried out a review of the published studies and have reached some conclusions. One of them is that the existence of different levels of serotonin in the brain of people with and without depression has not been proven.

There are also no differences in the cellular receptors for serotonin. There are even indications that serotonin activity increases in people with depression, which is the opposite of what would be expected. The fact that most of the patients participating in the studies have taken antidepressant medications could explain this contradictory fact.

Studies also show that depression cannot be induced by causing a reduction in serotonin levels. There is also no evidence of an association between variations in the gene that controls the production of the protein transporter and the incidence of the disease.

Depression can be caused by stressful events

instead yeah there is strong evidence to establish a relationship between having suffered stressful life events and an increased risk of depression.

The authors of the study question the usefulness of antidepressant medications. The drugs are supposed to work through their effects on serotonin and norepinephrine. But the evidence for norepinephrine’s role in depression is even weaker than that for serotonin.

Whether the effect of antidepressants is due to the emotional numbing they cause, it’s not clear that they do more good than harm, the authors say.

The researchers add that depression patients can fall into pessimism assuming that the cause of his disease is a brain chemical imbalance.

It’s important for people to know that the idea that depression results from a “chemical imbalance” is hypothetical, they explain. Although the effect of antidepressants on the brain is unknown, they caution that patients should not stop taking the drugs without first talking to their doctor.

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