Science is always growing. New science debunks serotonin-hypothesis of depression.

Part of problem with being an evidence-based chiropractor is that you gotta repeatedly keep up with research. Sometimes new research challenges our existing knowledge base, and this is particularly problematic because it means our clinical practice would have to change.

Today, we are going to talk about depression. Yes, you are right in that depression is outside the scope of chiropractic. That doesn’t mean we can’t share research about it. Especially since the overlap between chronic pain and depression is high.

Did you know research is able to demonstrate that depression predicts chronic pain? And we knew about this relationship since two decades ago!

What is depression?

serotonin hypothesis, depression singaporeWe are not going to talk about the DSM-5 diagnostic criteria for depression because that’s truly out of the chiropractic scope. But we do want to clarify what we mean by depression. According to World Health Organisation, depression is a mental disorder. It’s characterised by low moods or a loss of pleasure or interest in activities nearly everyday for two weeks.

If you are familiar with depression, you’d probably heard of the serotonin hypothesis. Serotonin is a neurochemical in the brain that is purportedly important for mood regulation. Specifically, scientists hypothesised that low serotonin levels in the brain can contribute to depression.

This effectively gave rise to the multibillion SSRI (selective serotonin reuptake inhibitors) drug market. SSRI, a type of antidepressant, is designed to stop serotonin from being reuptake in the brain. The end result of this is more serotonin in the brain, and effectively increasing serotonin levels.

Does SSRI work for depression?

prozac, ssri
SSRI is a multibillion dollar industry that has found its way into pop culture Prozac Nation is a memoir by Elizabeth Wurtzel which documents her experiences with depression

You would seem so? You may have heard of Prozac (fluoxetine), which is a commonly prescribed antidepressant for depression and pretty much a recommended drug across all clinical guidelines for depression.

The problem, though, is that big research studies are not able to convincingly demonstrate that it works.

A systematic review and meta-analysis (i.e., crème de la crème of research studies) two years ago reported that 60%-70% of the patients do not experience remission with SSRIs. The response can also be poor with 30% to 40% of patients not showing a significant response!

In studies that were able to demonstrate positive results, the difference between SSRI treatments and psychotherapy (e.g., cognitive behavioural therapy) is small. In other words, you can get just as good treatment results by opting to talk to a clinical psychologist or counsellor (i.e., medication may not be absolutely necessarily).

Does it work? Who knows. It challenges my bias a little to say this but probably not.

New study debunks the serotonin hypothesis of depression

ssri depression, antidepressantA new study published yesterday have openly declared war on the serotonin hypothesis. Published in Molecular Psychiatry, the authors found no evidence linking serotonin to depression and no evidence that low serotonin levels causes depression.

Both Twitter and mainstream news has gone absolutely crazy over this. Major news outlet have covered stories on this: The Guardian, The Telegraph, The Economist, The Conversation, Stylist, Evening Standard, The Independent.

Unfortunately for us in Singapore, there’s no coverage by Straits Times, Today, Channel News Asia, or any local media outlet has covered it.

What happens now?

Honestly? Probably nothing. Evidence-based medical practitioners and psychiatrists may start to reconsider prescribing SSRIs for depression but most doctors will probably continue to prescribe as before. Given clinical guidelines still do largely support SSRIs, it’s unlikely that prescription patterns will change anytime soon.

I would agree that FDA (U.S. Food and Drug Administration) would have lots of explaining to do. What was their basis of approving SSRIs as a drug, and also was the evidence compelling enough to warrant its approval?

Beyond that, I don’t think anyone is going to hold big pharma responsible. Yes, at the end of the day, consumers can choose against SSRIs but it’s unlikely to happen if doctors are to continue prescribing SSRIs.

Furthermore, in the United States, big pharmas have launched multibillion-dollar campaigns directly to consumers. Even though a research paper had established that advertising claims on the benefits of SSRIs were baseless, nothing is stopping the propagation of the marketing myth.