To quote from the editorial:-
Importantly, these findings [the Lancet study] do not support the widespread calls in the popular press for more people to take antidepressants because the meta-analysis and underlying trials do not examine who or how many people should be treated.And, despite the hope of the Lancet article, the BMJ editorial concludes:-
[T]he way many of the results were reported does not allow clinicians to extract clinically meaningful take home messages to inform conversations with patients.
This is partly because the Lancet study used odds ratios rather than risk ratios. It did not provide evidence about the proportion of people that improved on placebo. The typical placebo response in other literature is 30-40%. Using the average odds ratio from the Lancet study means about 10-12% more people in the treatment group would benefit compared to placebo. So, roughly 8-10 people would need to be treated for one of them to benefit compared to placebo.
Patients need to know that roughly 40% of people in antidepressant trials improve with placebo and 50% in the treatment arm. As the BMJ editorial says:-
Knowing that roughly 80% of patients who get better did not improve because of the antidepressant underlines the importance of starting with low doses, systematically re-evaluating the need for treatment after a response is achieved, and not accepting any enduring adverse effects.I would also add that it’s important to realise that a good proportion of people are not helped even in the clinical trials.
The BMJ editorial, therefore, usefully highlights the limited clinical scope of the Lancet study. We need at least to also focus on potential harms and long-term treatment. And, we need to ask whether the small statistically significant difference in clinical trials between active and placebo treatment could be an artefact due to placebo amplification (eg. see previous post).