Increased Frequency of Self‐Reported Obsessive‐Compulsive Symptoms in Patients with Functional Movement Disorders

BACKGROUND: Functional movement disorders (FMD) are associated with a high prevalence of psychiatric comorbidities. OBJECTIVE: To assess the frequency of obsessive‐compulsive symptoms (OCS) in FMD. METHODS: A total of 167 consecutive patients with clinically definite FMD (mean age = 44.4 years, standard deviation [SD] = 12.0, 119 females) and 145 healthy controls (mean age = 43.2 years, SD = 11.8, 103 females) completed the Obsessive‐Compulsive Inventory‐Revised (OCI‐R), which is a widely used tool for assessing OCS. The cutoff score ≥21 is indicative of clinically significant obsessive‐compulsive disorder (OCD). Motor symptom severity was assessed using the Simplified FMD Rating Scale (S‐FMDRS). All subjects completed questionnaires for depression, anxiety, pain, fatigue, cognitive complaints, health‐related quality of life, and childhood trauma. Personality traits were assessed using the Big Five questionnaire. RESULTS: FMD patients had higher mean OCI‐R score and higher proportion of individuals with OCI‐R ≥ 21 42%, 95% confidence interval (CI) = (30.2, 54.6) versus 16%, 95% CI = (8.2, 28.2) in controls, P < 0.001. Patients had higher scores in three domains: checking, ordering, and obsessing (P < 0.001). FMD patients with OCI‐R score ≥21 had higher depression, anxiety, cognitive complaints, and lower quality of life compared to those with score <21 (P < 0.001). No correlation between OCI‐R and S‐FMDRS scores was found. CONCLUSIONS: FMD patients reported higher rates of OCS compared to controls, along with higher rates of non‐motor symptoms and lower quality of life. This finding may have clinical implications and raises the possibility of shared risk factors and common pathophysiological mechanisms in FMD and OCD.