Perhaps it comes from a deficiency in the neurotransmitter serotonin. We've also been told that antidepressants work by reversing this deficiency. Source: Karolina Grabowska/Pexels For example ...

In 2016 over 70 million antidepressants were prescribed across the UK, more than twice the figure a decade ago. Concerns are regularly raised in the press that these drugs might be over-prescribed.