My daughter sees bugs that are not there and becomes very scared, Why?

How old is your daughter?

Seeing bugs is a classic example of methamphetamine use. Or it could be a sign of some kind of mental illness. You should talk to her doctor about it. :-/

She may just have an over-active imagination. My husband's cousin has loads of imaginary friends, and one time one of them "died." She was distraught. At the time, her great-grandmother had just passed away, and it seems like she was acting through what she had heard about that through her imaginary friends. Maybe your daughter saw something on TV or heard somewhere about some scary bugs? Ask her about it, and see if you can help her come up with some solution to get rid of the bugs. Maybe a spray bottle with water (which you tell her is bug spray) would make her feel better, or something along those lines.

EDIT:

I'm assuming your daughter is like 2 or 3. If she's much older, than it's probably not her imagination. I'd take her to the doctor and get her checked out.

You should take her to a psychiatrist and pay special attention to events leading up to these episodes. She could be seeking attention or she might be actually hallucinating. Either way, a mental health professional would be able to help you sort it all out.

She's a kid and has an active imagination. Monitor her television shows and see if any have bugs or spiders in them.

thats a side effect of cocaine...... doubt that is it.... but maybe she is trying to get attention or maybe she has an over-active imagination........