Those are something, at least, but they don’t actually serve as cites for the part pharmacologists want: better efficacy relative to the severity of negative side effects.
You shouldn’t be surprised at that characterization about withdrawal: flat-out cold turkey opioid withdrawal ALWAYS takes about a week, because that’s how long it takes the neurons to go back to producing more-or-less regular quantities of the neurotransmitters that work with the opioid receptors. (That doesn’t mean the addiction goes away-- just the gross symptoms of acute opioid withdrawal.) “Relatively mild” doesn’t help, either; again, with all the opioids, someone taking only a little of the stuff on a regular basis is going to have mild withdrawal symptoms, while someone accustomed to taking a lot is going to have severe ones. Kratom is still sold as a plant, with relatively little active ingredient in it and a lot of other things in it in addition to the opioid, so it’s tricky TO consume enough of it to have a serious opioid habit. (Modulo the purity issues, of course; if the “kratom” is actually oregano and fentanyl, that’s a whoooole 'nother ballgame.)
Similarly, while respiratory depression activity “less than morphine or codeine” is hopeful (and Wikipedia cites to the Raffa book on the point, which is at least kinda credible), that’s not uncommon; opioids that are relatively slow to bind to the receptors show less of that effect. (See Opioids and the control of respiration; the point’s discussed in the paragraph just below Figure 3.) The real question is HOW MUCH less, and to what extent it comes with the usual tradeoff: reduced effectiveness as an analgesic. (This tradeoff is why the opioids usually prescribed for pain relief, like morphine, aren’t the same as the opioids prescribed for opioid withdrawal, like methadone and buprenorphine.)
It’s not like scientists (and fellow travelers like me) just heard of kratom recently. Folks have been looking at it since the 1970s (Some observations on the pharmacology of mitragynine). Pharmacologists aren’t proud; if there was any evidence the stuff wasn’t just Yet Another Opioid, we’ve had plenty of time to take note of any weirdnesses about it.
Fortunately, there exist real compounds that have been PROVEN to be especially useful for opioid withdrawal, complete with diminished potential for abuse, notably the aforementioned methadone and buprenorphine. (Also dating from the 1970s.) Improved access to real drug treatment programs is the slow, painful, expensive way that works.
