1. Can weed make you hallucinate?
In large doses, yes. Marijuana is a mild hallucinogen.
2. Can weed worsen mental illness/trigger schizophrenia?
It can trigger depression from the endorphin imbalance, otherwise no.
3. When you are under the influence of weed, is it difficult to act like you're sober?
No
4. Is weed very addictive?
No. It's not chemically addictive, it's psychologically addictive, which is very easy to break.
5. Does weed affect your judgement?
No
6. Is quitting the use of weed associated with withdrawal symptoms?
As far as physical symptoms, absolutely nothing. Mentally, it leaves you feeling down, which depends on the potency, quantity, and frequency of use.
7. If you're feeling anxious or low to begin with, will weed just strengthen those feelings?
It doesn't change feelings of stress, it may compound them only if weed adds to the stress (parental problems, etc).
8. Is there a lot of bad/contaminated weed out there?
For the most part, no. No one to date has overdosed on weed. If you get laced weed, it's going to be much more expensive and the dealers going to tell you its laced. On the off chance your dealer gives you laced weed without you knowing, he's a ****ing *******. Weed laced with embalming fluid will **** your day up.