A review of past scientific work on the study of depression showed that the hypothesis of the association of this disease with serotonin deficiency has never been experimentally proven. The article was published in the scientific journal Molecular Psychiatry.

The authors of the work pointed to a number of studies in which it was not possible to find any correlation between various aspects of the work of the serotonin system and the development of depression.

In particular, in one of the experiments, scientists compared the amount of serotonin and its metabolic products in the blood and in the brain in healthy people and patients with depression, but did not find a significant difference between them. In other studies, the level of serotonin in volunteers was lowered artificially, with the help of a special diet. A more detailed analysis of the experiments showed that not all participants in the experiment develop depression.

The idea that depression is the result of abnormal brain chemicals, particularly serotonin, has been influential for decades and provides an important rationale for the use of antidepressants, the authors of the paper recall.

"Our comprehensive review of major serotonin research shows that there is no strong evidence that depression is associated with or caused by lower serotonin concentrations or activity," the study authors wrote.

The link between low serotonin levels and depression was first proposed in the 1960s and gained wide publicity in the 1990s with the advent of selective serotonin reuptake inhibitor antidepressants.

“Although it has been questioned in recent times, the serotonin theory of depression remains influential, mainstream English textbooks continue to give it expert support, it is held by leading researchers, and much empirical research is based on it. Polls show that 80% or more of the general public now consider it established that depression is caused by a "chemical imbalance." Many general practitioners also hold this view, and popular websites often cite this theory, ”the authors of the work note.

Molecular Psychiatry is a peer-reviewed scientific journal published by the Nature Publishing Group. It covers research in biological psychiatry.