I would think Crack Cocaine, Heroin, and Methamphetamine are similar to in harm to others (and there’s no way methamphetamine is that much less harmful to others, unless he’s not aware that smoke and production of it are toxic). I’m guessing most of that comes from it being illegal and people needing to steal to get it, so even more surprising is how harmful alcohol is to others even though it is legal. Full paper: https://www.ias.org.uk/uploads/pdf/News%20stories/dnutt-lanc...
Some of the criteria are that might fall under harm to others are:
For judging harm it's interesting how the culture and economics around a drug may chiefly determine the harm, not the substance itself. The measurable harm of different drugs varies across regions.
As far as I know.... unlike the US, the UK doesn't have a large community of dependent meth users. The level of distribution is low and if some did become available, it would probably be used by poly-drug users as an alternative/combination to other party drugs and not give much of an on-ramp to habitual use. The measurable harm would be acute health events like heart issues etc. and not the consequences of long-term use.
