Images in the mind
I have spoken to a number of people over recent weeks, all Christians, who have been troubled with intrusive thoughts. These are often sexual or violent in nature and, whilst recognised as the persons own thoughts, they are not the thoughts the person wants to have and they are seen as revolting and unpleasant. Sometimes, there are rituals that make the thoughts go away and sometimes there is just a period of escalating anxiety until the thought is finally (and unhappily) thought about, after which anxiety decreases. To all intents and purposes, this sounds like features of an obsessive-compulsive illness, but I think it has a special meaning for Christians.
These images are guilt-inducing - "why am i having them, am i bad?" There is forgiveness available in Jesus - and the people I have met seem to know this. But over time there can be niggling doubts about this since the problems don't seem to resolve or go away. In fact the harder you try, the more difficult it is. If I say to you "don't think of an elephant" what is the one thing you think of!
This over-focussing is one reason why they are not going away - that in order to make progress, you have to allow the thoughts to happen at some level and realise that no harm will come. Resisting them just makes it worse. This is the essence of the cognitive-behavioural approach used to treat problems like this. The trick is not to go on to the compulsions as well, but to stay with the anxiety until it fades - which it will after an hour or so. Here, having a faith can be helpful since it is another factor helping the person stick with the unpleasant anxiety. Maybe we can meditate on Jesus who surely understands something of this from the times when he was tempted.
Prayer is not the only answer here - psychology is needed too. But for a Christian, there are aspects of the faith which will help the psychology. I've mentioned a couple - what others are there?