Are you mad? Nobody suddenly becomes 'addicted'. Addiction is something you do willfully and deliberately to yourself. Addiction is not a disease, it is a form of self-harm.
In his examples addiction is a mental illness/disorder. I agree, it is really hard to understand why would anyone get addicted to something out of thin air, but it happens apparently and it is a very big problem. Most of the homeless people you see out there are not just mentally ill; they are addicted.
"Self-harm" you mentioned is a mental problem. Yes, none of these are like cancer and deadly at first, but they really can turn deadly if no one helps. It is hard for me to understand too, but I don't take anything for granted. We never know what would trigger all these. I am sure he didn't want to die at 35 and leave her 3 years old kid behind with his wife alone.
Are you mad? Nobody suddenly becomes 'addicted'. Addiction is something you do willfully and deliberately to yourself. Addiction is not a disease, it is a form of self-harm.