Harnessing Placebo Effects for the Treatment of Functional Cognitive Disorder: A Feasibility Pilot Study.

Objective: Limited research has directly investigated whether and how placebo effects can be harnessed for the treatment of functional neurological disorder (FND), despite a long-standing and controversial history of interest in this area.

Methods: A small exploratory study was conducted with adults with a cognitive subtype of FND recruited from a single cognitive neurology center in the United States. Participants were given the expectation of receiving cranial stimulation that could benefit their memory symptoms; however, the intervention was sham transcranial magnetic stimulation (placebo). Outcomes included measures of short-term memory testing, subjective memory rating, and state anxiety before and after stimulation. After the study, the true objective and rationale for investigating placebo effects were explained in a scripted debriefing session. Acceptability of the study design and qualitative feedback were collected. Institutional ethics approval and signed consent were obtained.

Results: Three patients (female, N=2; male, N=1; average age=57 years) were recruited. Outcome data were analyzed descriptively at the patient level. Trends of improvement in subjective memory rating, but not objective cognitive test scores, and decreases in state anxiety were observed. After the debriefing session, all patients found the study design to be acceptable (ratings of 70%, 90%, and 100%), and two of the three patients believed that withholding mechanistic information about the intervention was needed to leverage placebo effects as treatment.

Conclusions: In the first study to prospectively investigate the feasibility of harnessing placebo effects for the treatment of FND, promising preliminary findings were obtained, and methods and resources for use in larger future studies are offered.