He was almost certainly prescribed SSRIs or anti-psychotic medication. If he stopped suddenly, there would be severe mental problems
Also, the psychiatrist should have requested all guns be removed from his house. (Whether is not he would comply would be a different matter.)
Junner was ok ‘til he just TOUCHED that nasty looking gun!
You need to do some reading on SSRI drug side effects. They are horrible. And have Homicidal/Suicidal warnings.
As a Reverist did he have Covid Jabs? There are some bizarre symptoms from them.