In the Netherlands this has long been the treatment of choice in heroin addiction. It works a bit like a nicotine replacement patch, it keeps the withdrawal at bay but doesn’t give a rush. The latter is important because rush reinforces addiction. At the same time that also leads to combined use, because the rush is what people miss and crave. Craving is the psychological part of addiction, and usually the hardest to overcome. Heroin not only has craving, but physical withdrawal as well, that makes you really sick. So methadone is part of the solution.
Back in the early 00s we started treatment in the form of heroin provision instead, for a small group that kept relapsing, and that works well in the sense of harm reduction (less crime, less OD, less nuisance for the wider community).However, the moral objections especially from Christian politicians (linked to the gluttony association) remained in larger society. Luckily this is an evidence based treatment and recognized as such, so it’s still in use today in the Netherlands, but only if all else fails.
Apart from that, sometimes going for full abstinence is unwise because of underlying conditions, especially psychosis, which can really exacerbate due to abstinence, even when people receive antipsychotic medication.
Heroin use has been declining quite steadily in the Netherlands, with 14.000 addict in 2020. the average age of users is climbing, being >40 years of age for quite a while. Because of that, the mental health organization I work for has opened a living facility for elderly drug users a few years back, where they can use as long as they behave, and are provided with food and shelter.
As far as I know, Switzerland was the first country in Europe that started providing clean needles, condoms etc for addicts to reduce harm. With us that’s still the case as well. We used to have mobile methadon provisions (the so-called methadonbus) where street addict could get their methadone, condoms and such, and if they were able to behave (not pick fights, not abuse personnel, no dealing or hustling) they could come to the outpatient facility.
I’m not sure how many Dutch are addicted to prescription opiates, but the data I can find points to a marked increase in presciptions. However, opiate related hospital admissions and deaths remain comparatively low.