Explain about figuring out or deciphering addiction?

Dependence: You must clarify the definition. Dependence is generally the physiological and psychological need for a substance based on frequent/chronic use. Dependence is not necessarily pathologic - it's simply a known result. Addiction however is defined as a pathological outworking of dependence. Said another way, addiction is dependence that leads to inappropriate behaviors (drug seeking, theft etc).

Change of habits: Many times, when someone develops a drug addiction, the drug is what becomes most important to them in their lives. They will often stop at nothing to get their drugs, and they might even become withdrawn from the rest of the world unless they find a way to incorporate their drug addiction into the world.