Can pill placebo augment cognitive-behavior therapy for panic disorder?

In a number of drug and psychotherapy comparative trials, psychotherapy-placebo combination has been assumed to represent psychotherapy. Whether psychotherapy plus pill placebo is the same as psychotherapy alone is an empirical question which however has to date never been examined systematically.

We conducted a systematic review and meta-analysis of randomised controlled trials (RCTs) that directly compared cognitive-behavior therapy (CBT) alone against CBT plus pill placebo in the treatment of panic disorder.

Extensive literature search was able to identify three relevant RCTs. At the end of the acute phase treatment, patients who received CBT plus placebo had 26% (95%CI: 2 to 55%) increased chances of responding than those who received CBT alone. At follow-up the difference was no longer statistically significant (22%, 95%CI: -10% to 64%).

The act of taking a pill placebo may enhance the placebo effect already contained in the effective psychotherapeutic intervention during the acute phase treatment. Theoretically this is an argument against the recently claimed null hypothesis of placebo effect in general and clinically it may point to some further room for enhancing the psychotherapeutic approach for panic disorder.