Emotion Regulation in Functional Neurological Disorder: A Multimethod Comparison of Intra- and Interpersonal Strategies.

OBJECTIVE: Emotion regulation (ER) difficulties are frequently reported in individuals with Functional Neurological Disorder (FND), yet most evidence derives from self-report data, and little is known about intra- and interpersonal ER preference and success under controlled conditions. METHODS: In a preregistered multimethod investigation, a web-based questionnaire assessed habitual ER difficulties and interpersonal ER in 109 individuals with FND and 88 healthy controls (HC). A laboratory component, conducted in a subsample of the questionnaire participants (33 individuals with FND and 33 HC), comprised two experimental paradigms examining ER choice and ER success during intrapersonal regulation (reappraisal vs. distraction) and interpersonal regulation (self- vs. other-guided reappraisal). In the experimental paradigms, ER success was indexed by reductions in subjective arousal and by startle reflex magnitude as a measure of defensive psychophysiological responding. RESULTS: In Study 1, individuals with FND reported greater ER difficulties, higher alexithymia, more childhood trauma, and reduced use of interpersonal ER compared to HC. In Study 2A, stimulus intensity predicted ER choice, with a shift toward distraction at higher intensities, while no significant group differences in intrapersonal ER choice or success emerged. In Study 2B, higher stimulus intensity was associated with a lower probability of choosing self-directed reappraisal over interpersonal regulation, and individuals with FND showed a non-significant trend toward reduced preference for interpersonal regulation. Interpersonal reappraisal was associated with lower startle amplitudes than intrapersonal reappraisal, consistent with lower defensive physiological responding during interpersonal regulation. Across paradigms, ER success did not significantly differ between groups. CONCLUSIONS: FND was characterized by pronounced self-reported intra- and interpersonal ER difficulties. The laboratory data did not provide robust evidence for group differences in momentary ER implementation, but these null effects should be interpreted cautiously given reduced power for interaction effects. Interpersonal ER may represent a clinically relevant domain in FND and warrants replication in adequately powered samples.