No contradiction, just some confusing wording.
Methadone does ease WD symptoms of heroin addicts, presicely because it is an opiate and will bind to opiate receptors for a long time, stopping craving and painful withdrawl sickness, and most addicts do report that methadone provides less euphoria (or high) than heroin or
morphine (others say that it is quite euphoric, so this may just be a matter of preference). The problem is that since methadone is an opiate, it has it's own withdrawl symptoms and shouldn't be stopped abruptly anymore than heroin. Most methadone clinics work to (very) slowly taper a person down to no methadone a day, but even these controlled tapers can leave a person WD sick for a few weeks.
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