If you’re looking to attribute this as drug related why not look at his ‘new’ prescribed drug first. Of course if you prefer to attribute it to an illegal drug the first one you should look at would be methadrine, followed by PCP, next crack, then perhaps heroin, lets not forget ketamine and finally cannabis. Of course, if you involve alcohol with any of the preceding it greatly increases the risk of violent behavior. There are also a wide range of illegally obtained prescription drugs that could be included.
I attribute to nothing other than this jerk decid d to kill people