What is the difference between a habit and an addiction? Is it related to practice meditation ? Can I say that our respected individuality is a kind of 'self accepted and adopted' addiction ?
It's more like an English language question. A habit is a routine of behavior that can be good, bad or neutral. From a Buddhist perspective, one can define addiction as clinging(Upadana) towards sensations. Addiction results in bad habits.  

Upadana paccaya Bhava - Paticca-samuppāda