It happens to me too. I can be going about my day, in a good mood, nothing awful going on in my life, and suddenly it comes out of nowhere: the mental picture of harming myself in some way. It's usually taking an overdose of Ativan or cutting my wrists (which I wouldn't have the balls to do IRL), but occasionally it gets pretty grisly, like looking down the barrel of my .38 or crashing my car into a tree at 80 MPH.

I have to say that this doesn't happen often anymore thanks to the antipsychotics. But every now and then I let my little brain wander off down dark passages that are best left unexplored, where these intrusive thoughts lie in wait.