The methylenedioxy-derivatives of amphetamine and methamphetamine represent the largest group of designer drugs. The most frequently used compounds are 3,4-methylenedioxy-methamphetamine (MDMA-ecstasy) and 3,4-methylenedioxy-amphetamine (MDA), first synthesised in 1910 (MDA) and 1914 (MDMA), respectively, to be used as an appetite suppressant. At the end of the 1960s, non-medical (recreational) use appeared in the USA, and in the middle of the 1980s in Europe. In Norway, MDMA and related compounds have been detected in forensic samples since the early 1990s. In order to bypass the legal regulations and to produce more potent substances, a number of related compounds have been synthesised, including derivatives with one or more substituents (methoxy, methyl, halogen or sulphur), attached at different positions to the phenylring of amphetamine or methamphetamine. A report from 1998 shows that 0.5-3% of the adult European population, mainly young people, has used ecstasy.