You're an outlier. The vast majority of people who smoke opium or experience euphoria from taking medical grade heroin will obtain the urge to do it more.

As a physician:

No, the 'vast majority' do not. I've supervised medical grade opioid administration to more than a few people, both acutely and chronically, and *folks without a pre-existing substance use problem* do not often develop one, especially if it's over the short term. The idea that "I give you an opioid and then BAM I want more!" is highly divergent from my clinical experience.

As a physician, you should know that using opioids to experience euphoria and pleasure is drastically different from using appropriate doses to combat the effects of pain. It's the euphoria and pleasure that triggers operant conditioning and the accumulation of ΔFosB that occurs in the vast majority of addictions[1]. Only after receptor downregulation does withdrawal avoidance become a factor, but once that occurs, it doubles the strength of the operant conditioning.

Use != Misuse, but use for pleasure is a direct precursor of misuse.

[1] https://en.wikipedia.org/wiki/FOSB?wprov=sfla1

dFosB also accumulates in chronic pain and in some types of acute and inflammatory pain.

The grand-parent comment to which I am replying describes near-instant addiction in the context of an opioid prescribed for pain control.

See, this is saying something else entirely. Also, do you have a source for this?

Would I do opium again? Sure. It was fun. Would I do medical grade heroin or morphine again, under controlled circumstances with a nursing staff dosing me? Yeah. It was fun. Did I have some weird urge to go out and do it frequently? Nope. But to be fair, lots of folks drink on more than one occasion as well. They get high more than once. They might even have more than one drink or hit in one day. Simply wanting to do something again doesn't mean anything. I've done acid more times than I can count, and I wouldn't call it a habit. The only drug that I'd probably do more often if it were not dangerous to do too often is MDMA because it feels spectacular (better than opioids, to me anyway), but I'd not even call it a strong urge.

This isn't addiction, nor is it anything uncontrollable in general.

Unless you are implying that folks get uncontrollable urges, and in that case, please back that up with facts. Though I've met my share of addicts, most things just aren't instantly addictive. Even heroin isn't that way - especially if you actually improve an addicts like (hence, troops addicted to heroin in wars came home to be non-addicts).

>> This isn't addiction, nor is it anything uncontrollable in general.

With as much respect as I can offer I think you should consider the following notion, which in my personal experience is an actual fact:

"Until and unless you have been an addict you truly cannot understand the experience. And subsequently you are not able to point out what is and is not addiction."

Asking for opinion: can one transfer experiences with non-drug addictions (videogames, promiscuity, social nets, etc) to the substance-abuse kind? How similar are these?

I think this can be done reasonably.

I believe the most-essential factor is this: loss-of-control over the behavior in question.

IOW, when the behavior takes places in spite of the individual wishing to stop, or committing to stopping -- then it is almost certainly "an addiction". It is the behavior that is most important, not 'substances' particularly.

The trouble is that it is very, very difficult for someone to recognize AND admit that they are unable to control some aspect of their behavior.

Most of us will create elaborate explanations to avoid admitting (to ourselves mostly) that sometimes we window up in a situations where we are completely powerless to control our behavior.