"What time I am afraid, I will trust in thee." Psalm 56:3
Obsessive Compulsive Disorder (OCD) is a serious problem and its symptoms are far more extensive than excessive hand washing and checking locks. In fact, some people with OCD may not feel compulsion to wash their hands or check their locks at all. OCD can manifest itself in various ways through excessive procrastination and doubting.
For Christians, OCD can certainly be a massive thorn in the flesh. However, it can also be fought and overcome to glorify God and His grace.
The only solution for Christians with OCD is blind faith. Reasonable faith fails them. Reasonable faith cannot sustain them. They may be persuaded by the evidence provided by reasonable faith for a season, but as soon as an uninvited compulsion, a groundless yet nagging doubt assails them, they can be sent into complete dismay.
Again, the only solution for Christians with OCD is to avail themselves of blind faith. This means throwing their whole lives on Jesus despite what compulsions come their way. Whenever a compulsion comes their way, they must forsake all reasoning, and rather, resort to praise and thanksgiving until the vicious season of trial passes from them.
As a more specific example, a dedicated Christian of many years may struggle with bouts of OCD. Such nagging and completely uninvited and groundless doubts may assail him, tempting him to enter a labyrinth of questions and reasonings in order to rediscover and reconfirm the identity of Jesus all over again. In a swift moment, all his past experiences with His Savior and all his knowledge of the Bible become like a blank sheet of paper, completely wiped clean to the extent he may even be tempted to ask, "Who is Jesus?" Experience and reason have completely failed him. At this moment, his only way of escape is blind faith that trusts without seeing, manifesting itself in praise and thanksgiving to a man called Jesus who is written about in a book called the Bible. It is only by thus enduring such panic-attack inducing torments of the mind that he will see himself through the darkness and back into the light. Yet, by enduring, and by gaining experience, through the power of the Holy Spirit, he can and will overcome, though he can never let his guard down completely. Truly such a person groans within himself waiting for the redemption of the body.
Despite the torment and the heavy cross that must be borne by Christians with OCD, I have a hunch that they will meet with magnificent glory in the afterlife, for they have truly been tested and know firsthand what it means to walk by faith and not by sight.
God give them the victory!