Forgive me, but I disagree.
Scrupulosity is often tied to things like OCD, but it should be kept in mind that there is, IMHO, a spectrum of scrupulosity.
Some cases are clearly psychological — for example, driving over a pot hole in the dark, but convincing oneself that the “pot hole” was actually a person who was struck dead. Unfortunate folks like this might absolutely drive themselves to despair worrying about this, despite all advice and reassurance, despite whatever their priest might tell them, despite all evidence to the contrary of their fears.
But other cases are just an inability to distinguish mortal from venial sin, coupled with a fear and anxiety and a pattern of interpreting one’s behavior as negatively and harshly as possible.
Obviously, there’s a psychological component here, but it’s also very, very spiritual, because one of its root causes is just a simple lack of trust in Jesus. It’s also a matter of ignorance: I think a lot of scruples are just a poorly formed conscience that doesn’t know how to look at behavior with the mind of the Church. For example, I take people who ask is this a sin? quite at their word — they don’t know if the act is sinful or not, while many people simply call them scrupulous. I think that’s an abuse of the term.
Anyway, my long-winded point is just that instantly invoking things like OCD can be a bit limiting, especially if a person exhibits no other traits of OCD in other aspects of their life.