Case (Late-onset epilepsy)

Observational study - no intervention. Participants with first seizure or new diagnosis of epilepsy, in adulthood.~Inclusion criteria for cases includes:~* diagnosis of LOE or first seizure after the age of 18.~* diagnosis confirmed or established at a tertiary neurology centre.~* sequential cases will be used; in the unlikely event that eligible cases outstrip capacity, an annual cap of the first 150 patients per year per cohort will be used.~Exclusion criteria for cases includes:~* another 'lesional' attributable cause for seizures including malignancy, stroke (excluding transient ischaemic attack), hypoxic brain injury, trauma, vascular or congenital abnormality of likely aetiological significance.~* people with migraine or headache syndrome can be included in case group - the presence or absence of a seizure syndrome is mutually exclusive between case and control groups, not the presence or absence of migraine.

Control (migraine)

Inclusion criteria for controls includes:~* established diagnosis of migraine.~* with or without therapeutic medications with antiepileptic properties.~Exclusion criteria for controls includes:~* diagnosis of epilepsy or confirmed seizure.~* 'lesional' attributable cause for seizures including malignancy, stroke (excluding transient ischaemic attack), hypoxic brain injury, trauma.~However, in both cases and controls, people with dementia, alcohol excess, recreational drug use or pre-existing small vessel disease will be included, as excluding these conditions would bias against the inclusion of the population who may benefit from this research and against the inclusion of patients with high risk of small vessel disease.