No link between depression and serotonin levels, finds major analysis

A evaluation of 17 earlier research finds no proof for a hyperlink between despair and low serotonin ranges, which SSRI antidepressants concentrate on – although not everyone seems to be satisfied by the findings

By Sarah Wild

There could also be no hyperlink between serotonin ranges and despair, in keeping with an evaluation of 17 research. This raises questions on antidepressants that target this brain-signalling molecule, say the authors of the evaluation. Not everyone seems to be satisfied by the findings, although.

The serotonin speculation, which dates from the Sixties, says {that a} chemical imbalance within the mind, together with low ranges of serotonin, also called 5-hydroxytryptamine or 5-HT, results in despair. We now suppose numerous organic, psychological and environmental components play a task, however the preferred antidepressants, referred to as selective serotonin reuptake inhibitors (SSRIs), enhance the provision of serotonin within the mind.

Now, Joanna Moncrieff at College Faculty London and her colleagues have finished an “umbrella evaluation” of 17 systematic critiques and research, which collectively included a whole lot of 1000’s of individuals with and with out despair.

It’s tough to immediately measure real-time serotonin ranges within the mind, so the 17 research checked out despair and proxies for serotonin, such because the molecules in cerebral fluid that serotonin breaks down into; the degrees of serotonin receptors and the way lively they’re; or whether or not there are extra genes for serotonin transporters – which take away serotonin – in individuals with despair.

Moncrieff’s group discovered that there was no proof that low serotonin exercise or quantities trigger despair.

“The implication of our paper is that we have no idea what [SSRI] antidepressants are doing,” says Moncrieff. One chance is that they’re working by a placebo impact, she says.

Nonetheless, Johan Lundberg on the Karolinska Institute in Sweden says a limitation of the evaluation is that it didn’t distinguish between individuals who had ongoing despair and those that have episodes of despair, whose state on the time they had been assessed may have an effect on the functioning of their serotonin techniques. “It’s key to individually analyse information from research that study the identical sufferers when sick and when in remission, to have optimum situations to look at the speculation,” he says.

Moncrieff says the evaluation was depending on the research that had already been finished, none of which highlighted any distinction between individuals who had been experiencing signs of despair or had a historical past of it.

“It have to be recognised that 5-HT is probably going just one contributor to despair,” says Paul Albert on the College of Ottawa in Canada. “Given the massive placebo impact in remedy of despair, it’s possible that the contribution of different techniques, together with dopamine that’s implicated in placebo impact, could also be better than that of 5-HT.”

“Antidepressants are an efficient, NICE-recommended remedy for despair that can be prescribed for a spread of bodily and psychological well being situations,” a spokesperson for the Royal Faculty of Psychiatrists advised the Science Media Centre within the UK, referring to remedy pointers from the Nationwide Institute for Well being and Care Excellence (NICE) in England.  “Antidepressants will fluctuate in effectiveness for various individuals, and the explanations for this are advanced. We might not advocate for anybody to cease taking their antidepressants based mostly on this evaluation, and encourage anybody with considerations about their remedy to contact their GP.”

Journal reference: Molecular Psychiatry, DOI: 10.1038/s41380-022-01661-0

Want a listening ear? UK Samaritans: 116123; US Nationwide Suicide Prevention Lifeline: 1 800 273 8255; hotlines in different nations.

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