What is the difference between an extreme interest and drive to do something and addiction? The big difference is being addicted to something means you are physically and mentally dependent on it. It is a mental disorder of sorts. It doesn’t include just substances, but also activities. Even those who are dependent on social media or video games are technically addicted.
The question is if athletes are addicted or just very dedicated. Often times, boxers and martial artists find themselves unable to give up the sport, and will often find excuses to be around the sport even when their health fails them. Younger individuals in particular can become addicted to many things. This is because their brains are more receptive when young.