Have we become too reliant on antidepressants?

One in seven British adults – almost nine million people – now take antidepressants. Yet a study attached to the University of California San Francisco suggests we don’t actually know if they should. The paper from the US, led by William Ward and published last month, exposes a glaring flaw: American trials test these drugs for months, while in the real world patients take them for years. In the UK, for example, just over 25 per cent of patients have been taking antidepressants for five years. This gap raises a question medicine has faced before: how do we know our treatments work?

For centuries, doctors did more harm than good. Bloodletting was done because patients and doctors both believed they could see it working, overestimating their ability to see patterns in the storm of natural variation. They were wrong, but the lesson is not that people in the past were fools – rather that observation and experience of medical phenomena can be misleading.