Background: The underlying mechanisms of functional cognitive disorder (FCD) are still poorly understood. This hinders diagnostic identification and establishment of personalised and effective treatments. We aimed to describe the precipitating factors for new-onset FCD and explore differences between the acute and gradual onset FCD groups.

Methods: Retrospective analysis of a consecutive sample of FCD patients seen in three dedicated clinics in the United Kingdom between September 2023 and March 2024. Only patients with at least one-year symptom duration were included. We extracted mode of onset and precipitating factors, demographics, comorbidities, family history of cognitive symptoms, personal exposure to dementia, symptom duration and trajectory, as well as cognitive testing when available.

Results: Ninety-three patients were included, of which 45 had an acute onset of functional cognitive symptoms (48% of total). Of the acute onset group, 51% were female; mean age of symptom onset was 44 years (± 12). In the acute onset group, COVID-19 (n = 18, 40%), head injury (n = 16, 36%) and migraine (n = 16, 36%) were the most common precipitating factors for symptom onset, followed by cardiovascular/vasovagal events, dissociative episodes, panic, medication change, medical procedure under sedation and acute vertigo. The acute onset group was younger, most commonly had a fluctuating course of symptoms, and more headache and fatigue than the gradual onset group.

Conclusions: Functional cognitive disorder often begins acutely. The circumstances around onset may have treatment and prognostic implications. Similar to other functional disorders, the experience of abnormal cognition from an acute pathophysiological event can act as powerful precipitating factors for functional cognitive disorder.

Keywords: COVID‐19; brain injury; cognitive disorders; functional cognitive disorder; functional neurological disorder; migraine; precipitating factors; life event.

© 2025 The Author(s). European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.