Grain of salt caveats are indicated here.
Note the lack of mention of the recovery of any drug
paraphernalia, such as syringes.
This could be just the Russians trying to explain to
themselves why anyone would do this.
Recall that during the Soviet era, communism was "rational",
and thus anyone who opposed it was crazy, so dissidents
often found themselves committed to mental institutions,
where various "therapies" would be forcibly applied to
attempt to "cure" their diseased thinking.
The leadership must think that the modern Russian just
can't accept that such monstrous acts would arise from
mere ideas, ergo, there has to be another explanation.
I've seen articles on FR stating that a lot of the Falluja terrorists are drug addicts, our guys found drugs and drug paraphenalia.
The fact that some or a lot of these a*holes may be on drugs doesn't excuse them in the least. It's just another black mark against them. Drugs or not, they are 100% responsible for the evil they do.
I could shoot heroin or take other drugs and I still wouldn't kill innocent people, and neither would you.