Some subset of people do some subset of drugs in order to have an exciting/fun/heightened experience (e.g. cocaine on a night out to feel more confident and energised)

Some subset of people do some subset of drugs in order to settle addictive pressure (e.g. popping one’s codeine pills for the day)

Some subset of people do some subset of drugs in order to gain psychological or insight or have spiritual experience (e.g. taking psilocybin with an appropriate setting)

While the lines can be blurry, these are distinct use cases each with their own risks and considerations so they’re worth separating out.

The distinction you're making isn't the drug, it's the purpose, and you left one out: people also take drugs for medical reasons, with or without a prescription (aspirin is a drug).

For example, weed can be used for all five of those purposes. But what's the value you see in separating them?

Yep, exactly. Sure, I've left out medical reasons but principally it's not what most people have in mind when they talk about 'doing drugs' - even replacing aspirin with something psychoactive (e.g. SSRIs or anti-psychotics).

My point was in response to the parent's 'is it so much different really' question - when you insist that all varieties of reasons that people might be ingesting psychoactive substances stay under the same banner it's a fair bit harder to have a useful conversation about it.

> wriggling around on the floor on a big dose of LSD for 12 hours is casual clean fun?

Yes.