Amphetamines, which are favored to maintain alertness over prolonged periods of work, are even cheaper, but as their efficacy is inconsistent, they are less popular now with the younger crowd.
至於傳統適用於長時間工作、以提神為主的安非他命，雖然更便宜，但因藥效不同，在青少年間受歡迎程度已不若以往。