Firstly i don't believe Methamphetamine causes psychosis. What it causes is a lack of sleep. People who have been awake for several days, irrespective of whether they take ice or not will invariably go into a psychosis if they do it constantly and without respite.
Methamphetamine isn't particularly toxic to organs. Its not cariogenic like alcohol and won't cause kidney or liver failure after chronic use. The ROA is however important as is the purity. If users simply injected the drug (as opposed to smoking it) in a clean controlled environment, under supervision and were given education and support about how to deal with stress and mental health issues then its quite likely the violence that is associated with Methamphetamine would be greatly reduced.
Would legalised ice prevent long term meth psychosis or violent behaviour? These appear to be the bigger problem than increase in robberies. Prisons are not being filled with posession charges rather violent acts committed under the influence. These current problems exist because purity and availability have increased. Is there really much benefit from introducing a meth maintenance programme?
The problem with the word legislation is that people think it would be a free for all if it became legal.
I would argue that legislation means regulation and this is something we're sorely missing with drugs. The problem is that anyone, irrespective of their financial, family and emotional state can gain access to powerful substances that can enable people to create enormous harm. The problem is that people blame the drug when the real root cause are the problems in the person's life that compelled them to get high.
Methamphetamine should be available from the clinics that are already distributing methadone and suboxone. Users would be required to register for a program. Users would be asssesed as to their functionality. Dysfunctional users, with poor housing, employment and criminal/legal statuses should be required to attend daily to dose whilst functional users would be given takeaway doses after the clinic had evidence that you could safely take meth.
Users with violent mental health issues would continue to be dosed but in a controlled environment which would definitely reduced the likelihood of violence.
I have a relative who is a ice fiend and is doing several years for attacking police and with the intent of causing grievous bodily harm all whilst in the middle of a Methamphetamine associated psychosis. The problem was that he was in the middle of a particularly bad break up with his partner. They were fighting constantly and he had pre-existing mental health issues.
Because of the relationship problems he was using Methamphetamine and crack frequently and because he was high he wasn't taking his meds. After several days of not sleeping, drinking like a fish, and using Methamphetamine the fighting got violent. When the cops arrived he charged at them with a weapon.
The thing is that the police and time served will not have motivated him to stop using. I know the moment the idiot is released he is going to get high. He can't help himself.
The money we've wasted on police, lawyers, judges and prisons could have been spent on putting him on a program where he could dose on his drug of choice in a safe and controlled environment, where he would be required to take his meds and get regular sleep if he wanted to keep getting dosed. A well funded resourced drug management centre could give him the life skills and help to deal with interpersonal problems.
As we've seen by the evidence in countries that give heroin out these centres have helped people immensely, with large numbers choosing to quit using.
Throwing them into prison simply doesn't work.