Depression isn’t caused by low serotonin, study finds

There is no “irrefutable” evidence that the Depression is associated with low levels or activities of serotonin, suggests a British study published in the scientific journal Molecular psychiatry, last Wednesday, 20. Scientists involved in the review assess that the chemical imbalance theory influences patients’ decision to take and continue using antidepressants, in addition to encouraging further studies regarding the effects of these drugs on neurochemical systems. They warn that no one should stop treatment without medical advice.

“The popularity of the ‘chemical imbalance’ theory of depression has coincided with a huge increase in the use of antidepressants,” lead researcher Joanna Moncrieff told the University College London (UCL) website, where she taught. “Many people take antidepressants because they have been led to believe that their depression has a biochemical cause, but this new research suggests that this belief is not based on evidence,” she continued, who is also a consultant to the British Health Service (NHS). ).

Co-author of the analysis, Mark Horowitz said the research has also shed light on the influence of external factors on the condition. “An interesting aspect of the studies we reviewed was the strength of the effect of adverse life events on depression, suggesting that depressed mood is a response to people’s lives and cannot be reduced to a simple chemical equation.” university website.

According to the study, the serotonin theory was first suggested in the 1960s and widely disseminated in the 1990s, alongside the advent of selective serotonin reuptake inhibitors (SSRIs). As the name suggests, the drug inhibits the action of neurotransmitter transport protein and allows an increase in its concentrations in the synaptic cleft.

Since the start of the pandemic, sales of antidepressants and mood stabilizers have increased in the country, according to a survey by the Federal Council of Pharmacy (CFF). Between 2019 and 2020, the increase was 17%. The first five months of 2021, compared to the previous year, saw a 13% increase in trade. More than 42.9 million units were sold between January and May last year.

British scientists have therefore decided to carry out an “umbrella” type review of studies from research fields on the relationship between serotonin and depression. Meta-analyses and systematic reviews have focused, for example, on the action of neurotransmitter receptors and transporters. Some of the research has involved tens of thousands of patients.

The conclusion was that studies with moderate or high evidence did not support the chemical imbalance theory. In contrast, those that indicated a relationship between the neurotransmitter and the disease had low-certainty evidence.

Although the analysis did not focus on the effect of antidepressant drugs and the researchers do not say to stop their use without medical advice, they call for more studies on the effect of these drugs and also about treatments to deal with stressful or traumatic situations in people’s lives. , such as psychotherapy. Moreover, they consider that patients should no longer be informed that depression is caused by low levels of serotonin.

“Thousands of people suffer from the side effects of antidepressants, including the severe withdrawal effects that can occur when people try to stop them, but prescription rates continue to rise,” Moncrieff said. “We believe this is partly due to the false belief that depression is caused by a chemical imbalance. It’s time to let the public know that this belief is not supported by science.”

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