This happens when nothing else seems to work. A time of anxiety brings this on.
The obsessions in the Ultra Religious world are the exact same things as classic OCD (Obsessive Compulsive Disorder) , [i.e. cleanliness, food preparation, obsession with sex, holy places. numerology and gematriot.
The leaders tend to be people that have an exaggerated version of this OCD.
And this is the basic reason why the Ultra Religious world is seen to be insane.
OCD has nothing to do with Fear of God but to the religious world it is the same thing. The more focuses on rituals one is the more holy they seem..
So, in spite of the great thing that Reb Israel Salanter did in emphasizing Musar and Fear of God, still there is this troubling side of things in which fear of God can't be discerned or told apart from a diseased imagination.
For this reason Reb Israel Salanter himself focused on the more rational books of Musar Ethics from the Middle Ages more than the later Musar books which were all fused with kabalah and probably were written by people with this disorder. The obsession with religion is not the sign of a healthy personality, even though being true to the word of God in the Oral and Written Law is important.
[After spending time with the religious, you will start noticing this just as I did. A lot the people there simply have diseased imaginations.]
You can see why in Lithuanian kinds of Yeshivas obsessive religious behavior was rigorously excluded in order to prevent these kinds of crazy people from joining. Thus in the ultra Religious world you have people at the heads of the cults have different levels of OCD, but that is rare in the Litvak world which tends to exclude this kind of insanity.