Is it possible to forget your Name, Age and Birth date?

[Louise]

if you haven't seen your passport for 3 years? or is he just lying to me?

My friend calls himself "david" and i'm practically the only person who calls him by that! others would call him by a different name he had given them. it doesn't bother me the name ALTHOUGH he told me he was 30 the next minute he told me he doesn't know because he can't remember the year he was born! and he doesn't know his birthday.. is that possible??? because i haven't seen my passport for about a year now and i still know my name! age and birthday! lol