Anti-depressants, Ritalin, Adderall, Antipsychotics, Anticonvulsants, Barbiturates, Benzodiazepines, SSRI's (the most evil drug in the world), Seratonin...that's not even dealing into the household products that alter perception. I don't know much about this (did some research when a seemingly happy friend committed suicide 2 days after being put on an SSRI) but I know enough that there are millions of legal products which do alter perception.