Are you a deranged pig on drugs?

No

There are test which will specify the type of drug one has taken. Some simply say the category of drug taken. If you are looking for a specific drug, a test can definitely be done

they find certain chemicals found in that drug like THC in marijuana

Inverse Agonist.

drug-drug interaction is when two or more drugs interact pharmacodynamically in such a way that the toxicity of one or more drugs are altered.while drug desease is any negative feedback a drug come...