I wonder would just accepting this help? I realised lately talking to somebody suffering from similar intrusions, how often I have intrusions when engaged in conversation...........My intrusions are usually of the mundane kind "What will I cook for dinner tonight" "Must remember to buy X" (I think everyone gets these!). The point is that I can dismiss them easily (usually) because I don't have any emotional response to them i.e. I just accept them. Mindfullness could be useful here, in learning to 'defuse' from thoughts.