A lot of anons have said things like:
"All those other shooters must have been on SSRI's and in therapy too". But nobody has ever posted a source that actually confirms that for any previous shooters or patsies.
So, if someone is looking for a focus to dig, I think this is a good one. If we can show a pattern of at least 3 shooters who were in therapy and/or treated with SSRI medication, then we have a solid lead.