Anything less is an assumption based on rumor
https://www.canada.ca/en/health-canada/services/substance-us...
"Mental effects Fentanyl causes: dizziness confusion going "on the nod" (being in and out of consciousness)
Physical effects
Besides strong pain relief, fentanyl produces effects such as: drowsiness slow breathing nausea and vomiting smaller (constricted) pupils itching or warm/hot sensation on the skin"
I think the mental effects cover what was shown in the videos provided by the other commenter.
Here is a video (https://www.youtube.com/watch?v=uVtvp59xue4&t=884s&t=14m44s) of someone "nodding off" or doing the "Hastings Shuffle." There are two people being interviewed who said that's what they look like when they've taken heroin. They went on to describe taking fentanyl and almost dying. Fentanyl is an opioid like heroin but it's much more powerful. If you don't die or overdose, then you'll be shuffling around.
This video (https://www.youtube.com/watch?v=kgEdyvxwcvQ&t=5m45s) has two examples of people injecting drugs at a safe injection site and appearing to "nod off." One slumped over a chair around 5 m 50 seconds and another around 6 m 10 seconds.
edit to add another video: https://www.youtube.com/watch?v=F1ojeXgyAu0&t=2m8s this one is fucked up but shows someone injecting and then the after effects. They think it's heroin, but the narrator says it could be fentanyl and they can't know for sure. Around 3:30 is the after effects.
Probably not convincing because you don't really see what the drug they are using is and you don't see them stick the needle in their arm or press the plunger.
I don't have crime stats because they don't arrest people for drug possession or even giving it away for free where I am. (https://www.straight.com/news/vancouver-police-department-de...)
There are lots of mental health problems and other contributing factors of people who use street drugs, including using drugs that aren't pure. We have coroners reports on deaths with fenatnyl and other drugs in the deceased. https://www2.gov.bc.ca/assets/gov/birth-adoption-death-marri... But that doesn't discuss the behavior. I don't think the behavior is solely attributable to fentanyl, but it does contribute to a fair bit of it since it's in so much of the supply.
Anyway, there is lots out there if you're interested in searching more.
I'm sure none of this convinces you, and I'm sure nothing I type or show will convince you either.
Coroner data is not useful in this case as deaths are not necessarily correlated with other behavioral abnormalities.
You don't need to be a researcher to find arrest records with behavioral descriptions and record of substances confiscated
Health records are different due to HIPAA, generally those are much harder to get your hands on even when deidentified