High Quality Content by WIKIPEDIA articles! Designer drug is a term used to describe drugs which are created (or marketed, if they had already existed) to get around existing drug laws, usually by modifying the molecular structures of existing drugs to varying degrees,[dubious discuss] or less commonly by finding drugs with entirely different chemical structures that produce similar subjective effects to illegal recreational drugs. The term designer drug also technically applies to the new psychiatric medications, such as the SSRI's and atypical anti-psychotics, as they are designed over many years using testing in animals and neuro- imaging.