Across mental health and behavioural problems, ‘Dodo bird’ findings that bona fide therapies have similar effects have turned attention to the ‘common factors’ they share rather than how they differ, a paradigm shift increasingly evident in the addictions.

Jerome D. Frank’s book Persuasion and Healing published in 1961 is acknowledged as the most influential early exposition of the ‘common factors’ understanding of treatment – a process he conceived straightforwardly as the attempt “to enhance a person’s feeling of well-being”. Asserting in 1961 that “much, if not all, of the effectiveness of different forms of psychotherapy may be due to those features that all have in common rather than to those that distinguish them from each other” amounted to a revolutionary undermining of the competition for validity between different schools of therapy. These claims, he implied, were missing the point; their cherished methods and understandings of psychological distress were not active ingredients but platforms (an important role nevertheless) for the less esoteric features they shared – features which were not just the province of psychotherapy, but also seen in religious healing ceremonies, in the prescription of a placebo, and in the more everyday ways others help “demoralised” people regain traction over their lives..........