Thread by @allyrooney

You might have seen this review in the news, which finds little or no evidence that low serotonin causes depression. The way it’s being reported in parts of the press is misleading. Here’s why: (1/10) nature.com/articles/s4138…

The study design that tells us whether a treatment works is a Randomised Controlled Trial (RCT). There is good evidence from analyses of hundreds of RCTs that on average, antidepressants are better than placebo tablets at treating depression. (2/10)

The study reported today is not an RCT and can’t say anything about *whether* antidepressants work.

Instead it examined a widely-known theory relating to *how* they might work: the theory that depression is caused by low serotonin. (3/10)

The study found inconsistent or no evidence to support that theory. The results suggest that the ‘low serotonin’ theory of depression is wrong, or too simplistic, at least in most patients. (4/10)

This has been known or suspected for years and isn’t that surprising. Like @docbloomfield says, everyone knows headaches can be treated by paracetamol, but no-one thinks headaches are caused by ‘low paracetamol’. (5/10)

The study tells us little about what antidepressants actually do in the brains of depressed people (my answer: lots of other stuff besides serotonin reuptake inhibition = many other possible mechanisms of action). (6/10)

So - we don’t know exactly how antidepressants work. This study doesn’t change that and it’s always good to highlight where more research is required. We DO know that they must work somehow. The study doesn’t change that either. (7/10)

Cue media hysteria with articles or headlines, reporting this study, implying that 'antidepressants are not grounded in science'. Statements like this are deeply misleading and potentially harmful. Antidepressant grounding in science is e.g. here (8/10) pubmed.ncbi.nlm.nih.gov/29477251/

The *theory that depression is caused by low serotonin and by extension antidepressants must work by fixing that* is not supported by science. Good riddance - depression is a complex disorder caused by many things, treatable by many things, including antidepressants. (9/10)

Antidepressants do not suit every individual but they are well-evidenced for populations. Please don't be misled by lazy headlines into stopping any prescribed meds without speaking to your doc first. (10/10)