It is really not sufficient evidence for the metaphor, though. The point may be that it is akin to "drugs" but not all drugs are like heroin and what he is des

It is really not sufficient evidence for the metaphor, though. The point may be that it is akin to "drugs" but not all drugs are like heroin and what he is describing is nothing like heroin cravings and withdrawal. Why not go with something that invokes less emotions in the reader like "caffeine" or "nicotine"? Because the itch to check on a notification or scroll through the news feed is surely closer to the itch for a cigarette or your vaporizer than... heroin. That's a big jump there just to describe "compulsive desire".