In your example, I agree with you, they do have an addiction. It does not contradict with what I said. The person not needing to stop and their inability to sto

In your example, I agree with you, they do have an addiction. It does not contradict with what I said. The person not needing to stop and their inability to stop if they tried are two different things. Heroin does form a chemical dependency, where it could even be life threatening to quite cold-turkey, and therefore it is addictive. Unlike mental illness, addiction is defined by formation of a dependency. sometimes that dependency is at the biological/chemical level, sometimes it is a psychological dependency (can be caused by mental illness), not nevertheless a dependency must exist that prohibits the addict from functioning without the cause of the addiction. Bad habits can cause adverse impacts just as addictions can, and addictions (like coffee - which forms an actual biological rewiring/dependency, people get severe migraines when trying to quit it) can be harmless unless you're trying to quit.