Comment on Iranian crystal a misunderstanding of the crystal-meth

I read with interest the study conducted by Karrari and colleagues regarding “Iranian crystal a misunderstanding of the crystal-meth” published in your journal.[1] In this study, the authors have explained that the pattern of substances of abuse is varied in different parts of the world, also in Iran, and the main ingredient of street named drugs is different according to city or country, for example Crack is kind of cocaine, but in Iran is heroin that may also contain amphetamine, ecstasy, and/or corticosteroids with different amounts that make it even more harmful than pure heroin or any other drugs.