hi ernst, friends, would you correlate a placement of interchange of 12 lord sun, with lagna lord mercury , while sun also conjunct venus in this first house of virgo lagna with an expression of OCD?
No, for OCD you need something going on with the moon.
the moment you get a person with a Saturn moon conjunction you are dealing with a person who is limiting what they are allowing into their world - this is due to the fear factor of this conjunction.
Venus starved or shamed, especially by moon, would support OCD as its venus that makes the little things feel okay, with a starved or shamed venus, a lot of things can just not feel good to a person and so this can trigger them to obsess about things. The 12th house influence can cause a person to want to hide, and of course, many OCD things are having an element of wanting to hide something. So yes, what you are looking at can contribute to this.