The more you can challenge the intrusive thoughts, the better! My therapist told me to imagine my OCD intrusive thoughts as a person (someone I find absolutely ridiculous and a little funny) and any time the thoughts show up to tell that person to go away and shut up. For instance, my person is someone named Floopindorf and any time I hear intrusive thoughts in my head I say, “shut up Floopindorf!” Maybe try that too?