Had both sadly.
Background:
Drinking - 6 very strong European beers (8-9% alcohol per can) per day for 2 years (and 10+ years of weekend binge drinking before)
Opiates - Very strong kratom addiction (ongoing), no kratom extract but 10 full spoons of kratom per day for 2,5 years.
Result: The winner is alcohol, hands down. 3-4x times worse, but you know it's kratom, no heavy duty illegal opiates (would never try them, disgusting, especially the IV stuff, thought makes me puke).
Both are horrible, and very similar, alcohol has that added, strong sharper anxiety, panic, on the verge of seizure (never had an actual seizure luckily), not sleeping for days, aggression is stronger and you feel poisoned, like shit too, and you reek of alcohol too, bloated, ugly, fat alcoholic body. At least with opiates you leave a pretty and slim corpse

(lost 20+ kilos on kratom).
With alcohol, one beer doesn't even stop the withdrawal, you need to get really drunk twice, three times in a row to get completely rid of the anxiety (believe me I know, didn't quit at first try, 50 tries or more), with opiates one smaller dose ends the withdrawal. I had also worse depression with alcohol, but opiate wd lasted longer (now I take only 1-2 spoonfuls of kratom per day, one day kratom-free per week, still an addict not lying to myself, kratom is not a miracle cure is trading one addiction for another but significantly better one).
Alcohol is poison, opiates help (at least kratom) helps you live a better, happier life, just make sure to be smart, be humble, and never greedy (and have kratom in the house at all times if you are an addict.... :D, otherwise you get the wd)
UPDATE: I live with chronic fatigue syndrome (kratom helps a lot with that) and was diagnosed with depression and anxiety issues (but I don't have depression, it was all alcohol related).