A new report casts serious doubt on the whole serotonin = happiness thing

But please don’t stop taking your SSRIs just yet.

Medical pills placed in the shape of a smiley face
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Mental Health

If you’ve kept up with memes in the past few years, then you know that young people on the internet are obsessed with serotonin, a neurotransmitter that’s supposed to make us happy. But a recent large-scale review of several studies found that depression actually might not be caused by low levels of serotonin, a pretty damning conclusion when you consider that several modern antidepressants — known as SSRIs, or selective serotonin reuptake inhibitors — focus solely on increasing the levels of that exact chemical in our brain.

The review, published in the journal Molecular Psychiatry, was conducted by researchers at University College London who analyzed 17 existing studies and found no clear evidence linking low serotonin levels to depression, per New Scientist. Among those 17 studies was one in which life circumstances turned out to be a very strong driver of depression, and another in which participants’s serotonin levels were artificially lowered but did not cause depression in people who didn’t already have it, according to The Guardian. Instead, researchers concluded that serotonin is likely just one small piece of a larger puzzle, and depression is likely caused by a variety of factors, including genetics and physical environment.

Understandably, this analysis has caused major waves in the scientific community, as well as for many of us who take SSRIs. The science behind SSRIs was first developed in the late 1960s, when scientists found that people who had died by suicide had lower levels of serotonin in their brains, per the National Center for Biotechnology Information. Then, in the 1970s, scientists developed the first SSRIs, which blocked the absorption of serotonin by nerve cells and thus made the chemical more available to other nerve cells.

So if this new report is to be believed, what is that wave of relief some of us feel when we’re on SSRIs? It turns out that part of it might be that extra serotonin, but the University College London researchers believe a big part may be the good old placebo effect.

Before you flush your Prozac down the potty, it’s important to note that not all experts are in consensus, and this review has sparked some backlash. Psychiatrist Johan Lundberg, a professor at Sweden’s Karolinska Institute, told New Scientist that the review didn’t distinguish between people in various states of depression, which he believes is an important factor.

Meanwhile, The Royal College of Psychiatry warned against heeding its advice and noted that antidepressants do provide very real physical and psychological benefits for people at risk of suicide, according to The Guardian. So definitely do not stop taking your antidepressants just yet — especially if you haven’t spoken to your doctor — but do keep in mind that the thing standing between way of you and everlasting joy might be more complex than a lack of happy hormones.