Time agnosia, otherwise known as time blindness, is relevant to both autistics and ADHDers, but not necessarily for the same reasons.

The autistic person that has disappeared down a wonderful rabbit hole of hyperfixation, hyperfocus, special interest – all really amount to variations of the same thing – loses all sense of time because we are entirely focussed on the task in hand, to the exclusion of all else.

The ADHDer, whilst also enjoying periods of hyperfocus, it is now believed, experiences neurological processing delay (reading the entry on Ritalin ← click here would be useful at this point) so that time moves much more slowly for us, even though it seems, from the outside, that we are moving at speed. Consequently, it is often very difficult for ADHDers to estimate how much time has passed, how much time a particular task will take, or even which task we actually finished first (do we finish tasks?).

Here’s some further reading: It’s an article with an excellent title – click here to read it → Coping with Time Agnosia (Time Blindness): an ode to burnt noodles.