Explaining How Psychotherapy Affects the Brain Can Increase the Perceived Effectiveness of Psychotherapy: A Randomized Controlled Trial

Past studies repeatedly found that biological explanations of mental disorders cause laypeople and clinicians to doubt the effectiveness of psychotherapy. This could be clinically detrimental, as combined pharmacotherapy and psychotherapy is often optimal. The distrust of psychotherapy is theorized to stem from dualistic reasoning that psychotherapy, perceived as occurring in the mind, does not necessarily affect the brain. The current study aims to mitigate this belief in a randomized controlled trial. Participants (individuals with symptoms of depression (n = 262), the general public (n = 374), and mental health clinicians (n = 607)) rated the efficacy of psychotherapy for a depression case before and after learning that the case was biologically caused. Participants also received either an intervention passage describing how psychotherapy results in brain-level changes, an active control passage emphasizing the effectiveness of psychotherapy without explaining the underlying biological mechanisms, or no intervention. Unlike the active control and no-intervention control conditions, the intervention caused participants to judge psychotherapy as significantly more effective than at baseline even though they learned that depression was biologically caused. An intervention counteracting dualism can mitigate the belief that psychotherapy is less effective for biologically caused depression. Future research should examine the durability of this intervention in clinical settings.