Disease modeling in functional movement disorders.

Area of Science:

• Neurology
• Psychiatry
• Social Neuroscience

Background:

• The underlying mechanisms of functional movement disorders (FMDs) remain largely unknown.
• Investigating the role of social and familial exposure to movement disorder models is crucial for understanding FMDs.

Purpose of the Study:

• To determine if exposure to movement disorder models within social networks (family/friends) contributes to the development of FMDs.
• To explore the influence of phenotypical congruence of the observed disorder model on FMD development.

Main Methods:

• A case-control study design was employed, comparing 33 patients with FMDs to 66 age- and sex-matched controls with organic movement disorders.
• Conditional logistic multivariable analysis was used, adjusting for relevant covariates including age, education, disease duration, comorbidities, and clinical phenotype.
• Exposure to phenotypically congruent and incongruent movement disorder models was assessed.

Main Results:

• A significant association was found between FMDs and exposure to phenotypically congruent movement disorder models (OR=3.9, p=0.01).
• Exposure to a similar movement disorder model from friendships showed a stronger association (OR=5.9, p=0.04).
• No association was observed with phenotypically different neurological or non-neurological disease models.
• Greater exposure to a concordant movement disorder model correlated with an earlier age of disease onset.

Conclusions:

• These findings provide evidence that disease modeling, particularly through social learning, is a significant contributing factor to the phenomenology of functional movement disorders.
• The results highlight the importance of considering social and environmental influences in the etiology of FMDs.