Unfortunately I have taken high doses of this stuff(600-700mg). For me it is very dissociative, your own voice sounds far away, you can't put words together coherently or remember anything. All the while you see hallucinations which are better described as delusions. You can hallucinate people, even talk to them. It's very common to hallucinate bugs. Basically it's schizophrenia in a pill. An actual overdose would usually take place after 900+mg, and would be the result of a dire lack of acetylcholine.