For one, drugs like ketamine, Ecstasy, and FM2 (flunitrazepam) are less harmful to the nervous system, and are generally considered to be "soft" drugs that the human body can cope with, as opposed to "hard" drugs like heroin, cocaine, and amphetamines. The former group are less addictive-frequent users are able to function without them and experience no withdrawal symptoms-than legal substances like nicotine and alcohol.
一來，像 K 他命、搖頭丸、FM2 等，屬於對神經傷害度較小、人體耐受度較高的「軟性藥物」（soft-drug）；相較於海洛因、古柯鹼、安非他命等對神經傷害較大、耐受度低的「硬性藥物」（hardcore），其「成癮性」──不吸就坐立難安、具有戒斷現象──較低，甚至低於可隨手取得的菸酒。