Functional Neurological Disorder, Sleep, and Dreaming: A Large Online Questionnaire–Based Study

OBJECTIVE: In this exploratory study, the authors used subjective participant data to investigate sleep disturbance in functional neurological disorder (FND) and its impact on FND symptoms. METHODS: An online questionnaire was designed in collaboration with FND charities and administered to 373 adult participants with a self-reported FND diagnosis. RESULTS: Most participants (86%) were women, and most (73%) perceived their sleep quality over the past 3 months as poor. Almost all (93%) reported nonpositive dream content, with 78% experiencing nightmares at least once per week. Self-rated bad sleep quality increased by 41 percentage points since the onset of FND, and the frequency of nightmares also significantly increased. Obesity was highly prevalent (44% with a body mass index >30 kg/m²), but formally diagnosed sleep-related breathing disorders were rare (8%). Many participants (46%) noticed symptom improvement after a good night's sleep. Most (88%) reported worsening of functional symptoms when falling asleep, during sleep, or when waking up. About one-quarter noted symptom changes after specific dreams or nightmares, with almost all (97%) reporting negative changes, which were more common among participants reporting poor sleep quality. Moderate rates of sleep paralysis and functional seizure were observed. Among those who experienced functional seizures, 74% reported that they arose during sleep. CONCLUSIONS: These findings support the common perception of poor sleep quality, nightmares, and negative dreams among individuals with FND and suggest that self-reported sleep and dream content may also influence FND symptoms. However, the authors recognize a high risk for selection and recall bias.