As a society, we are slow to the understanding that addiction is not a "bad habit" or a "character flaw." I have mixed reactions to calling it a "disease," because, while in many ways it behaves like a medical disease, it cannot be treated with bed rest and chicken soup. It also cannot be cured with medication, although some medications help in its management.
It has a genetic piece, but it is not simply genetic. It has a source in life experience, but, as has been argued multiple times, addicts and non-addicts can have very similar life histories.
Fortunately, many addicts do find ways to go into what could be called a remission, and are able to live normal — some might say, even better than normal — lives.
"Recovery" starts with stopping the use of whatever substance is involved: marijuana, alcohol, opioids, etc. With alcohol, especially, a medically supervised detox is highly recommended. Alcohol detox is especially risky, with the possibility of fatal seizures. Detox from other substances can be incredibly painful.
Once the person is "clean," maintaining sobriety is a serious process. AA has a saying, "It’s a simple program — all you have to do is change completely."
There are multiple forms of support for the first weeks and months of a person’s sobriety, psychotherapy being a valuable one. The newly-sober person has to learn to think about life differently, handle emotions differently, even find a new circle of friends.
It’s also important to be aware that family dynamics and society norms have a powerful effect on developing AND treating addiction. Widespread beliefs about what makes a person "strong" can lead to the idea that there are "good" emotions and "bad" ones. Many a sufferer has begun addiction as an effort to banish "bad" feelings. Addictive substances are mood-changers. If you’re angry, take a drink. If you’re frustrated, take a "hit."
A large piece of "recovery" is to create a new attitude towards oneself and others (hence the idea that some people in recovery are "better than normal"). Psychotherapy, both individual and group, is a powerful tool in this.
And there are the families of the addicts. Very often, when a person gets "straight" or "sober," the family first discovers that the addict’s behavior wasn’t the cause of most of their problems. Family members are surprised to discover that their first reaction to someone getting into recovery is more anger than relief. Once the addict changes, the family members are also met with the need for change, themselves.
All of this can lead to suffering. Depending on the individual, though, it can also lead to a spurt of emotional growth. Once again psychotherapy helps.