Quid claimed that it was due to a lack of trust in God. That shows he knows nothing about it.
People with OCD are plagued with obsessive, recurring, intrusive thoughts. One example is about whether or not they turned off the oven, or locked the door. And it's not due to short-term memory issues. They could clearly remember locking the door, but still not be "sure" about it. This isn't about confidence in God, but about confidence in self. Or another OCD person might wash his hands over and over again because he's not sure that he got everything. I knew a Traditional priest once who was diagnosed with OCD, who repeated the words of consecration over and over and over again, because he was never quite sure he got them right so as to make it valid.