This website is an accurate source of drug information, though relying on it for legal advice would be a bad idea given it's based on UK law.
EDIT: Note that in the 'drug deaths' section there's only 1 on record from LSD. Your health class has been feeding you bullshit.
EDIT 2:There are no known physical side effects associated with acid use, nor is there any evidence of brain damage. There are some psychological risks, however, particularly for those with a history of mental problems.