How sensitive is your startle reflex?

Tl;dr: I'm wondering if something in the ADHD brain makes us less likely to get startled.

I am extremely hard to startle compared to everyone else I know. It's almost impossible (but I can startle).

I was just doing research into the startle reflex, and research shows that stimulants like caffeine make people startle more easily and more hypersensitive (I'm hypersensitive and have Sensory Processing Disorder), but caffeine actually makes me less sensitive (as does alcohol), and even less likely to startle than before.

So just curious, how easily startled are you? What makes you more likely to be started and less likely?