Psychotherapy beats placebo for depression only by a small margin, a placebo researcher argues

In an Oxford University Press chapter, psychologist Jens Gaab argues that psychotherapy and open-label placebos are close relatives, noting that therapy's specific advantage over placebo controls in depression is small and only marginally above the threshold for a clinically meaningful difference.

A therapist and patient talk in armchairs with an open bottle of plain white capsules on the table between them.
Share this:

Talk therapy for depression does outperform placebo, but not by much. That is the sobering backdrop to a chapter by psychologist Jens Gaab arguing that psychotherapy and placebos, especially placebos given openly, are closer relatives than either field likes to admit.

The chapter, “Why psychotherapy is an open-label placebo and open-label placebos are psychotherapy”, appeared in October 2023 in the Oxford University Press volume Placebo Effects Through the Lens of Translational Research, edited by Luana Colloca and colleagues.

A small edge over placebo

Gaab revisits Hans Eysenck’s notorious 1952 claim that psychotherapy works, as far as it does, through nonspecific or placebo effects. Eysenck was probably wrong, he writes, because several psychotherapies for depression do significantly better than control conditions, including placebo controls.

But he cites evidence that once known sources of bias are adjusted for, the specific effect is small, only marginally above the cutoff for a minimal meaningful difference in treating depression. Meta-analyses he draws on found therapies beat “nondirective supportive” control groups only when researcher allegiance was not controlled for. Direct comparisons with pill or psychotherapy placebos showed a significant advantage, but one below proposed cutoffs for clinical significance.

Placebos without the deception

The chapter’s larger point concerns open-label placebos, which patients take knowing they are inert. Placebos, Gaab writes, have moved from “methodological chaff to therapeutic wheat”: from a deceptive control in trials to a treatment that is both effective and ethical once the deception is dropped.

If a placebo can work when patients are told the truth, he argues, its real nature is that of a psychological intervention, in other words psychotherapy. The chapter considers how open-label placebos could function as a form of psychotherapy, and how psychotherapy could improve the way open-label placebos are used.

Study Details:

  • Title: Why psychotherapy is an open-label placebo and open-label placebos are psychotherapy
  • Authors: Jens Gaab
  • Journal: Placebo Effects Through the Lens of Translational Research (Oxford University Press), chapter 4.4
  • Publication Date: October 2023
  • DOI: 10.1093/med/9780197645444.003.0018