Is St. Nikodimos of the Holy Mountain describing here what pyschiatrists call obsessive-compulsive disorder (OCD)?
8. How the Spiritual Father is to care for those with thoughts of blasphemy and doubt
If it happens that you confess some people who have thoughts of blasphemy, or some people who always are in doubt and fear concerning their health and life, or concerning the salvation of their soul, on account of their thoughts, you should tell the first ones to disregard those blasphemous thoughts and not to think whatsoever that they are a sin, because they are not their own creations, but rather of that hater of good, the devil. Or you may tell them to rebut those blasphemous thoughts with these words: "Get thee behind me, Satan! I shall worship the Lord my God, and Him only will I adore. Your pain and your blasphemy shall return upon your own head in the present and in the age to come," just as St. John of the Ladder wisely counsels. To those having incessant doubts, either caused by depression and hypochondria, or by the devil, as a test or allowance of God, you should tell them: 1) to pray continuously to God; 2) not to believe in their thoughts, but rather to believe and to accept those things which you say to them; and 2) if it is possible, give them in writing the rule which you appoint for them, because as they are always in doubt, they will quickly be able to believe that which they see written.
Saint Nikodemos the Hagiorite, Exomologetarion -- A Manual of Confession Uncut Mountain Press, 2006, pp. 146-148
I am particularly interested in the thoughts of professional psychiatrists.
Begging your prayers,