My definition of addiction is as follows. Someone uses something, or even someone (usually the former) and get a feeling of euphoria, thus leading that individual to a pattern of using that substance to recreate that feeling.
Only problem is your body compensates for that over time to the point that the euphoric feeling becomes less and less each time while you need more and more to reach that "old feeling".
Pretty soon your body has come to RELY on this substance to maintain it's normalcy.....this is addiction.
When you have physical, mental and spiritual holes because you lack that substance then you are in the full on throws of addiction. When you can't even remember the actual high anymore, but do it to function daily....that is addiction.
Now, withdrawal is a totally different ball game. With addiction one of two things is likely to happen to you. You will either die from it, or realize you're dying from it and quit it.
(Some quit it only to start again to acheive once more that glorious "first high", but this is getting off track)
Withdrawal is only the process by which your mind body and soul must go through in order to cleanse itself and purge that need for that substance.
No one's ever died from withdrawal, as far as I know, not if it's monitored properly anyway. Though it may feel like you are.
Symptoms vary depending on what you use, but it can range from vomiting, to severe headaches, cramping, restlesness, loss of appetite, loss of sleep, weight loss, paranoia, the list goes on and on.
There are many many resources out there for coping with withdrawal, but no one can beat addiction until they get their mindset right first, no matter how hard you try you have to WANT it really bad first.
Everything we put into our body is a poison if you think about it. Everything we ingest is killing us slowly more and more each day. The thing about drugs is it does so on a much larger and faster scale and makes you feel good while it's happening.
Hope I helped.
Yes, I've battled addiction and won.