If LSD is not addictive how do you develop tolerance for it

FIRST:

You need to check your facts Ms. Bomullock. There is still LSD in the world today, there are still illegal manufacturers of LSD, and there are still people in the United States who use it recreationally. Sure it isn't as popular as it was in the 1960's, but it's still a drug that commands a share of the illicit drug black market. I have found it as recently as last summer in remote areas such as Idaho and in larger amounts (usually sheets of 100 hits) in more populated areas such as Portland, Oregon and Southern California. It's the same chemical it was 70 years ago when it was formally discovered and dealers stupid enough to sell poison (despite the fact that amounts necessary to kill cannot fit on a single blotter hit of lsd) to users would probably be getting their doors knocked down by very pissed off family members and /or friends of said users and the insuing clash would no doubt be making headlines in newspapers.

SECOND:

To Mr. Soccer Dork:

You are correct in that there is no physical addiction with LSD. A psychological addiction can occur, but people can become psychologically addicted to anything.

What happens when you take any psychoactive drug (from aspirin and caffiene to heroin and meth) is that the drug mimics neurotransmitters that already exist in your brain. Your brain has receptors to bond with these neurotransmitters and, when the drug takes effect, it bonds with the receptors blocking your naturally made ones and leaving them in the dust. But the brain responds quickly by making more receptors, to balance your body out. This is known as tolerance.