At least according to the Handbook of Exposure Therapies, exposure is the most effective treatment for anxiety, OCD, post-traumatic stress, and similar problems.  But most therapists don’t use it.  If you’re a health economist, it’s only natural to wonder why.  The Handbook has a whole chapter that tries to explain why best practice fails the market test.  It begins by observing that:

First, the majority of therapists simply do not use evidence-based treatments such as exposure therapy, even when they are aware of their existence.  Second, implementing exposure therapy in an effective or optimal manner is often easier said than done.

The chapter goes on to blame under-use on – and debunk – three “common myths” among practitioners:

(1) participants in randomized trials are easy, straightforward treatment cases with a single diagnosis and no significant comorbidity; (2) the result of treatment outcome studies, based on these simple, rarified samples of patients, will not generalize to real-world outcomes; and (3) exposure can be harmful, and will make people worse, or cause them to dropout from treatment.

I suspect that most economists would focus on the demand side.  Maybe patients think that the exposure cure is worse than the anxiety disease.  But this explanation doesn’t seem to work.  Therapy dropout rates are roughly 20%-25% for all the main treatments.  In 25 controlled trials of post-traumatic stress treatments, for example, “The average dropout rate was 20.6% for exposure-only treatments, 22.1% from cognitive therapy and anxiety management conditions, 26% from combinations of exposure and cognitive therapy or anxiety management, and 18.9% from EMDR.”

The authors of the chapter focus instead on the supply side, blaming under-use on, “lack of training (or inadequate training), therapist dislike of manualized treatments, and therapist fears that exposure therapy will have harmful effects” – and citing “lack of training” as the primary problem.  But this isn’t a very satisfying explanation.  They’re trained in something; why not this?

I’m not sure what’s going on either, but here’s my best guess.  Therapists, like other doctors, have a lot of slack because patients trust them and – as long as they’re insured – don’t worry much about costs.  Under the circumstances, it’s only natural for therapists to focus on techniques that they enjoy, and not worry too much about what actually works.  And if one thing comes through the Handbook, it’s that exposure therapy is ugly to watch.  It’s a lot more pleasant to spend an hour empathizing with a patient than pushing him to face his fears.  And if, as a side effect, your patients keep coming back because they still feel anxious, even better.