RE: Stop Speeding's disgusting antics
Dopaminergic stimulants cause really bad psychosis, this is a progressive deterioration and the threshold for psychosis gets lower and lower as the user rewires (read: trashes) their brain. Heavy users don't have to be up for days to start seeing shadow people, as a large dose will cause hallucinations almost immediately.
The effects tend to mimic schizophrenia (which is basically a condition related to unregulated dopamine) and basically the user will hear things, up to and including entire conversations between nonexistent entities, and "see" things, which aren't usually so distinct (shadows, movement) but combined with the paranoid mental state and auditory hallucinations gives a convincing effect that someone is there.
Psychosis is scary shit. On the heavier end, it's incredibly realistic to the victim and it is basically impossible to pull someone out of their delusion without forcibly injecting them with sedatives. Infamous cases of people mauling and eating others while under the effects of PCP are examples of full-blown psychosis. The user just KNOWS there are cops out there. They can see them moving around, see that? No? It's because they're hiding! I heard them say my name! On the lesser end, it's more like a temporary fixation that the user can hypothetically snap out of, but the effects of the dopamine cause an obsessive mental state where even after being distracted, the user will go right back to imagining cops/enemies/demons.
It's really fucking gross and this guy is a seriously debilitated drug addict. If he keeps using the effects will become more and more extreme - and they will do so rapidly.