Suggestibility in functional neurological disorder: a meta-analysis

Area of Science:

• Neuroscience
• Psychiatry
• Clinical Psychology

Background:

• Functional Neurological Disorder (FND) is a condition affecting movement and sensory functions.
• Suggestibility, or responsiveness to direct verbal suggestions, has been theorized as a potential predisposing factor for FND.
• Previous research on suggestibility in FND has produced inconsistent findings.

Purpose of the Study:

• To quantitatively assess whether patients with FND exhibit elevated suggestibility compared to control groups.
• To perform a meta-analysis to synthesize existing evidence on the relationship between FND and suggestibility.

Main Methods:

• A comprehensive search of four electronic databases was conducted (updated April 2020).
• Original studies measuring suggestibility using standardized behavioral scales or suggestive symptom induction protocols in FND patients and controls were included.
• Random-effects meta-analyses were performed on extracted data, calculating standardized mean differences (SMDs).

Main Results:

• The meta-analysis included 19 articles with data from 316 FND patients and 360 controls for behavioral scales, and 1285 FND patients and 1409 controls for symptom induction.
• Patients with FND demonstrated significantly greater suggestibility on standardized behavioral scales (SMD = 0.48).
• FND patients also showed significantly higher responsiveness to suggestive symptom induction (SMD = 1.39).

Conclusions:

• The findings support the hypothesis that heightened responsiveness to verbal suggestion is characteristic of FND.
• Atypical suggestibility may represent a cognitive marker and confer risk for developing FND.
• Understanding suggestibility in FND can inform diagnostic and treatment strategies.