The research
Studies consistently find that more than 90% of people experience intrusive thoughts — violent, sexual, blasphemous, or contamination-related. The thoughts do not reflect character or desire. They become a problem only when you fight them, fear them, or compulsively try to make them go away.
What helps
Notice the thought, label it ("that's an intrusive thought"), and let it pass without engaging. The harder you push, the louder it gets — this is the white-bear effect, well-documented in cognitive psychology. For OCD specifically, the treatment is exposure and response prevention (ERP), not reassurance.
When to seek help
If intrusive thoughts trigger compulsive checking, washing, mental reviewing, or reassurance-seeking that takes more than an hour a day or causes significant distress, this may be OCD — a highly treatable condition.