Jim: I'd just like to add my two cents to the discussion. My background is not professional but experiential. It's been 45 years since my last drink-no (other) drug history. There's been plenty of time for me to watch, read and learn.
You are right, withdrawal from opioids/alcohol can result in death which is why the medical community prescribes hospitalization in extreme cases to medically treat and monitor withdrawal with safe results.
Psychological counseling is also advised to assist with a healthier re-entry into society.
Even in the case of the withdrawal of a painkiller which has been properly used, a physician would taper the patient's dosage so as not to produce an adverse reaction to the lowered dose before the ultimate elimination of the drug.
As regards the subject of caffeine withdrawal, I don't think that is comparing 'apples to oranges', although I will attest that caffeine withdrawal can produce a nasty headache and ill temper.
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