Addiction is not a disease or a hereditary trait, it's a crutch that deeply unhappy people - people who feel unable to change their circumstances - use to make themselves feel better.
Addiction is more than drugs or alcohol: there is sexual addiction, food/sugar addiction, even internet addiction. These are all behaviours that provide a happy state of mind or a place where the addict can feel in control and can express themselves. These cannot be treated with pharmaceuticals, these need therapy and a willingness to change in order to find the reason for the unhappiness.
Everyone eats, why do some become addicted to food? Every surgery patient gets opiates in the hospital, why do so few become addicts? (Most) everyone fucks, why so few sex addicts? Addiction cannot be explained as an effect of the substance or action.
Addiction is why the stereotyical wife ballons into a bitchy hambeast after the wedding: she's unhappy and feels unable to change her circumstances and eats emotionally to feel better. It's why the substance user feels the substance helps them: they feel able to better express who they are without the social pressure to conform; it lowers their inhibitions.
Every day in hospitals around the world, people are given opiates like fentanyl and heroine. These are physically addictive drugs - they have withdrawal symptoms. Yet these people manage to quit the drugs without issue: granny didn't become a smackhead after her hip replacement. Given a socially vibrant environment where people feel comfortable expressing who they are, drugs/food/sex hold no addictive power. It's when people are in an environment which makes them unhappy, or they have internalized oppressive inhibiting behavioural codes that makes them unhappy, then they have potential to use a substance or act as a happiness crutch.
In short, it's some underlying stressor that drives people to addictive habits. It could be anxiety, lonliness, boredom/lack of purpose, depression, work/life stress, or a strongly external locus of control. Addiction treatment must address the underlying cause.
Rat park: an experiment in which rats stopped using opiate water of their own volition.