Is a lack of success with girls/sexuality a major cause for mass shootings?

[Schiff for Senate]

Perhaps it's a factor, but I doubt it's the primary cause.  Many people have this lack of success but are sane enough to realize that's no reason to go out and murder people.

This applies to most of the 'reasons' mass shooters usually have for committing their crimes, though.
For instance, in the 1998 shooting, the two shooters were bullied and isolated. Millions of kids have been bullied and isolated. The vast, vast, vast majority have not then committed mass shootings.