Low serotonin not the cause of depression

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Goodfellow Gems

Low serotonin not the cause of depression

Following a review paper on the relationship between serotonin and depression1, the lead author Professor Joanna Moncrieff, a Psychiatry Professor at UCL (London) notes2: “It is always difficult to prove a negative, but I think we can safely say that after a vast amount of research conducted over several decades, there is no convincing evidence that depression is caused by serotonin abnormalities, particularly by lower levels or reduced activity of serotonin.”

The popularity of framing depression around ‘chemical imbalance’ coincided with a huge increase in the prescribing of antidepressants. It is incorrect and unhelpful to tell patients that they are suffering from low serotonin levels in their brain as an explanation for depression.

This does not mean that SSRIs do not work, more that we don’t have a good understanding of their mechanism of action. 


  1. The serotonin theory of depression: a systematic umbrella review of the evidence. Molecular Psychiatry (2022)  View here
  2. No evidence that depression is caused by low serotonin levels, finds comprehensive review. Science Daily (2022) View here

Gems are chosen by the Goodfellow director Dr. Bruce Arroll to be either practice changing or practice maintaining. The information is educational and not clinical advice.

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