The chemical imbalance theory of depression is well and truly dead. A paper by Joanna Moncrieff and colleagues, longtime critics of the effectiveness of antidepressants, has caused a splash. The paper provides a summary of other summaries that confirm there is no evidence to support the idea that depression is caused by disturbance of the brain’s serotonin system.
They have done us a favour by corralling the evidence that says as much, even if we knew this to be the case.
But the death of the chemical imbalance theory has no bearing on whether antidepressants that affect the serotonin system are effective. These medications weren’t developed on this premise. In fact quite the opposite is true – the chemical imbalance theory was based on an emerging understanding of how antidepressants were shown to work.