I think it's a tough problem to solve: how far should we help drug addict in their addiction? Is the goal to help them survive, help them stop using drugs, help them find a job?
Depending on the metrics you will find that unconditional housing is more effective (ex: https://www.utoronto.ca/news/housing-first-more-effective-tr...) or offering incentives to stop is more effective (ex: https://www.chcs.org/resource/contingency-management-for-adu...)