Why do most people get better whatever treatment they have?

To add to the confusion about what different therapists do  – chiropractor, physiotherapist, osteopath, acupuncturist… – and who to see for what condition, is the common occurrence that people often get better whoever they opt to see.  It used to puzzle me how this could be, but understanding the many different effects of treatment: specific, non-specific and shared, provides some explanation.

A specific effect of treatment is one that is unique to that intervention.  A cortisol injection has a very specific effect on the tissue that it is injected into.  A targeted exercise at a particular dosage would also have a specific effect, strengthening muscle or stiffening tendon..

Non-specific treatment effects are those that not directly caused by the intervention but are due to context.  Natural history would be an example: time doing its work in recovery.  Another example could be that patients general present when symptoms are at their worst and so might be expected to return to their average level with or without intervention.

Shared mechanisms are those that are not specific to any one intervention: reassurance, relaxation, therapeutic alliance, education, placebo (an amplification of a treatment effect due to positive beliefs about that effect) are examples.

Research shows that often it is these ‘shared effects’ of therapeutic interactions that are having the most effect and explains why outcomes can be very similar from different treatments.  The more effective the specific treatment effect, however, the better still should be the outcome.  More about that in the next blog post about what makes physical therapists high-performing.