Everything that claims too, or actually does, control or seriously mitigate pain is addictive; and this includes the ugly formulas of rationalization used to suppress a guilty conscience, or to deny one has an addiction.

Pain killer addiction is commonplace; because on top of the pain blocking factors, the drugs deliver euphoric feelings, which require ever higher doses to maintain, leading eventually to with drawl symptoms (pain reliever-caused pain) unless proper dosages are maintained. Not too surprising that a creature with built in pain-reduction chemicals(endorphins) would be susceptible to opiate abuse, or any other drug that temporarily suspends either endogenous, or extraneous negative stressors.

The "experts" are now talking about video game addictions (ten percent of players) and sexual addictions (masturbation leading to rotator cuff injury). There are even pain addicts, getting their fix with needles / piercings and the cane of former cheerleaders turned dark mistresses
with cat-o-nine pom-pons. Perhaps anyone who has a lifetime vocation or hobby is indeed addicted to their fascination; perhaps addiction, like the money that attracts people like shit seduces flies, is necessary for civilization?