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

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.

An online questionnaire was designed in collaboration with FND charities and administered to 373 adult participants with a self-reported FND diagnosis.

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.

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.