In Colorado, the penalties run the opposite way from what the drug schedules would suggest. Colorado lists psilocybin in schedule I, C.R.S. 18-18-203, and ketamine in schedule III, C.R.S. 18-18-205. Yet personal use of psilocybin mushrooms by adults does not violate state law, while possessing any amount of ketamine is a felony.
Psilocybin Mushrooms
Psilocybin and psilocin are “natural medicine” under C.R.S. 44-50-103(13)(a). Under C.R.S. 18-18-434(5)(a), a person who, for the purpose of personal use and without remuneration, possesses, consumes, shares, cultivates, or manufactures natural medicine does not violate state law or any local ordinance, unless the section expressly limits it. The limits are narrow. A person under twenty-one who possesses or consumes natural medicine commits a drug petty offense under subsection (1), and so does anyone who openly and publicly displays or consumes it under subsection (2). Selling natural medicine for remuneration outside the state’s licensed program is not protected: subsection (5)(c)(II) provides that nothing in the section permits it.
Ketamine
Colorado’s drug statutes treat ketamine more severely than most of schedule III. Possessing any quantity of ketamine is a level 4 drug felony under C.R.S. 18-18-403.5(2)(a), where possessing a small amount of most other controlled substances is a level 1 drug misdemeanor under subsection (2)(c). For distribution, C.R.S. 18-18-405(2) groups ketamine with methamphetamine, heroin, and cathinones: more than 112 grams is a level 1 drug felony, more than seven grams up to 112 grams is a level 2 drug felony, and seven grams or less is a level 3 drug felony.