Again, as much as this is a symptom of much larger socio-economic and healthcare issues, we cannot let this things keep happening.
When you have Cancer, you don't just do chemo (long term, difficult and sometimes not effective at the beginning), but you also treat symptoms so that the patient can have quality of life until he's cured.
This is not so different. We can tackle the underlying poverty, mental health, addiction and houselesness issues broadly, with socially sensitive tools, but we also need to establish that, regardless of the reason, a lot of these people are committing crimes against other citizens and the latter also need protection and care.
We need more police presence in the streets (beat cops, especially Downtown), we also need an actual Transit Police, pay barriers in the LRT stations (as many of them as possible), we could do with the return of the loitering bylaw.