The retention of lacosamide in patients with epilepsy and intellectual disability in three specialised institutions.

•The usefulness of new AEDs in PWID deserves special attention.•We present a two-year retention rate of lacosamide of 57%.•This retention rate is similar to rates published for other new AED’s.•Behavioural side effects were more frequent than reported in the general literature.•One death occurred unexpectedly within two months after starting lacosamide, likely to be classified as a SUDEP.