Some people do seem to be unable to stop. Millions of people start college every year, and for the next four year, they drink to excess regularly. Then they graduate, get a real job, and almost all of them are able to adapt to life with a far lower level of alcohol intake. But a few can’t.
It’s not clear what is the deciding factor in this. Some of it could be an aspect of self-medication - the person has an underlying mental illness (e.g., chemical imbalance) or psychological issue (e.g., a history of abuse) - and the drug helps to cover it. For others, it could be a lack of impulse control. For yet others, it could be an addiction to the social aspects of the drugs, covering for shyness or fear of isolation. And some drugs are taken with particular goals in mind, to prompt (perceived) creativity, to stay amped up, to grow muscle, etc. So long as the goal exists, the person will want to continue.
Depending on the drug, there can be mystical components. The evidence would be that a drug like LSD or psilocybin causes you to experience things in accordance with how your imagination happens to work (some see colors, others see aliens, yet others see the face of God). So some end up having experiences that seem like they’re seeing answers to the secrets of reality, and become drawn into this, thinking that it’s important that they do so.
There’s a lot of reasons why a person might become addicted, but it’s going to vary strongly by the individual, as will the strength of the effect. Smoking, for example, is notoriously difficult to stop doing (supposedly). But some regular smokers simply decide to quit smoking, and do so without any particular difficulty, just as many people quit drinking as they come out of college.
But one thing to keep note of is that we’re all prey to our brain. Being “convinced” of something is a mental state. Thinking that something is “worth it” is a mental state. An alien species, with advanced technology, could theoretically program us to believe anything and to be absolutely certain of the correctness of that belief. How do you come back from that? Nothing external can be as convincing as something which is completely axiomatic in your head. Anything which contradicts it is clearly wrong, since the one truth is the measure by which truth is evaluated.
Depending on the individual, there’s some ability for drugs to form that sort of situation. By corrupting the signals and logic in your brain, you can become convinced of things due to spikes of dopamine, images of vastness, etc. and now that’s true, to because it got recorded as “truth” by the induced neural reactions.
But, it’s a random chance whether that occurs. Does the person have a strong need for something in themselves? Does the particular combination of drugs and mental states/images happen to align to produce a perceived answer for that need? If so, then that’s where things can go off the wall. If there’s no need and/or the drugs don’t hit the right spot, then it’s just a trippy but frivolous experience.
