I always thought this was sort of obvious.
Wards in no way "absorb" or "block" attacks themselves, they block the damage. So no, they definitely do not stop stifles, mezzes, stuns, and interrupt moves (all of which can interrupt you).
However, damage itself has a chance to cause an interrupt (and your normal counter to this is your Focus skill), so blocking damage still functions to lower your actual interrupts, because there are less chances to be interrupted. In a lot of cases, there are a lot less chances, since almost all CAs and spells inflict damage, alongside autoattacks, but only a few spells/CAs have effects that lead to interrupts.
And I'm quite certain any damage taken can trigger an interrupt - just look at DoT spells.