Those people are going to get drugs regardless. Wouldn't it be better if the governemtn could get the money and use it for health care or jail if it really is necessary (instead of allowing criminals to amass wealth and power)? Don't you think there'd be fewer junkies if they could work with a doctor and social worker to wean themselves off? The people peddling drugs are dealers who only exist because the government has criminalized the drugs. Every drug should be decriminalized and their should be much more of a focus on education then drug abstinence.
Drugs will be used more in poorer neighbourhoods. Putting some of the users in jail won't change that. Drug education, decriminalization/legalization and showing addicts that you will not penalize them - you will actually work with them - could make those neighbourhoods a lot less shitty.
It helped in portugal, although they just decriminalized drugs, they didn't legalize them.
http://mic.com/articles/110344/14-y...-all-drugs-here-s-what-s-happening#.l5C87gX5D
disclaimer - I don't know if decriminalization is better than legalization and vice versa. THat's why I kinda talk about both of them. The issue is the illegality of them though