I think that withdrawl is a possible reaction as a result of detox. I think, it describes a syndrome of signs/symptoms that occur or can occur as one's body no longer has a particular drug in it's systems.
Detox is getting the drug, and it's associated toxins, out of your system, the process if you will, generalized as a whole, as one word.
I also think that the term withdrawl was used alot in the past to describe getting off of any drug that could cause it, and now it's become the politically correct term to use the word detox so as not to hinder the process by attaching a negative stigma to addicts and their addictions.
I think that detox is getting the substances out of your system. (cause)
The withdrawls are the effects of the detox.
I have detoxed myself from medications without withdrawals. For example, I was on effexor and weaned off without withdrawals, and that's a major drug to get off of.
I've also used substances such as valium or xanix regularly & managed to get off slowly without going through hell.
As for the painkillers......humph....that was withdrawal from the devil!
Good question! I would say they are the same except I look at detox as the bad part of the withdrawal when the body is using every means to get rid of the toxins. Sweat, breath and all other bodily functions. This is just my view.
As far as I know they are the same.