I've lived in Glasgow tenements, four or five floors high and no lifts, only stairs (called a 'close') Old Victorian buildings, bit like those in the Gorbals.
No druggies in those days but many tramps/drunks sleeping in the close, and ladies of the night plying their trade round the corners under the stairs.
Out the back was the 'midden' or housing for the dustbins. Lots of happy rats lived in those!

Many were demolished and the tenants rehoused in soulless modern tower blocks (like that dreadful Grenfell Tower)
But the closes were jolly places, everyone knew everyone else. A scrubbing lady was paid to scrub all the stairs and whitestone them once a week. The rooms were quite classical with ornate plaster ceiling roses and cornices.
Teeming with life and quite cheery in my opinion. But grubby of course and could become slums.