Nearly every substance or chemical will have some withdrawal symptoms.
There have not been laboratory studies of physical or psychological dependence or abuse potential in humans caused by kratom. Suwanlert (1975) reported that following the chronic exposure to M. speciosapreparations, abrupt abstinence can be followed by opioid-like withdrawal symptoms in humans. Typical withdrawal symptoms include hostility, aggression, excessive tearing, inability to work, aching of muscle or bones, and jerky limb movements.
Going by experiences from others I’ve known, the withdrawal symptoms are similar in nature to quitting coffee.
Regarding physical dependence, ethnographic studies in SE Asia, some testimonials appended to the Pinney Associates 8-factor analysis, and the surveys by Grundmann (2017) and the Pain News Network (2017) suggest that abrupt discontinuation may be accompanied by withdrawal symptoms that are qualitatively similar but generally weaker than those observed following discontinuation of opioids. However, such reports make it difficult to disentangle the emergence of preexisting symptoms that had been mitigated by kratom use from those that occur as a physiological rebound accompanying the abrupt discontinuation of kratom use in kratom-dependent people.
And of course one known fact, is that kratom has not been studied in detail.
More studies of kratom’s potential to produce physical dependence, tolerance, and withdrawal are needed to characterize the nature and severity, and determinants of abstinence-associated symptoms. It is not completely devoid of signs that could be consistent with abuse or dependence, but neither is there evidence of high abuse/dependence potential that would support the conclusion that CSA scheduling is indicated.