One of the most important things I can say to a client with OCD who is tormented by violent, sexual, or otherwise disturbing intrusive thoughts is this: the presence of these thoughts is not evidence that you want to act on them. In fact, the research consistently shows that OCD sufferers have intrusive thoughts about the things that most go against their values. A loving parent has thoughts about harming their child. A devout believer has blasphemous thoughts. A gentle person has violent thoughts. OCD, counterintuitively, reveals what a person cares most deeply about.
The compulsive behaviours that accompany OCD — the checking, washing, mental rituals, reassurance-seeking — are attempts to neutralise the distress caused by the intrusive thoughts. They work, briefly, but they teach the brain that the distress was real and warranted, making the next intrusive thought more distressing and the next compulsion more necessary. Breaking this cycle is the work.