As a therapist, I have worked with dozens of people suffering from depression. Many of these people have been - wrongly, in my view - prescribed antidepressants by their GP. And not just for depression: anxiety, paranoia, eating disorders, OCD, even insomnia are now routinely tackled with this powerful medication.

Perhaps I sound like a Luddite, or possibly as a middle-aged man my values are distinctly pre-digital. Perhaps I just don't get the whole social media thing, which is moving so fast that old-fashioned values and morality are no longer relevant.

Mindfulness is one of those zeitgeisty health terms you may have seen bandied about in the media recently. But what exactly is it? How does it work? A...