If you've ever had a sudden, horrifying thought about harming someone you love – and then immediately felt sick to your stomach about it – welcome to the weird world of Harm OCD. This misunderstood monster has many people convinced they're secretly dangerous, when they're actually experiencing one of the most treatable forms of obsessive-compulsive disorder. These intrusive harm obsessions are usually ego-dystonic, meaning they're at odds with a person’s core values and cause significant distress – which is exactly why they feel so disturbing.