Colorado voters have passed a ballot initiative to decriminalise psychedelic mushrooms for people 21 and older.
The plans would come into effect in 2024 and would see other similar drugs added to the initiative in 2026.
Colorado becomes the second state, after Oregon, to vote to establish a regulated system for substances like psilocybin and psilocin, the hallucinogens found in some mushrooms.
They also plan to create state-regulated "healing centers" where patients can experience the drug under supervision.
It comes after state’s current approach to mental health has been criticised by supporters who argue that psychedelics should be able to use to treat PTSD, anxiety, depression, addiction, which they have always done.
However, critics have urged caution as the Food and Drug Administration has not yet approved the psychedelics as medicine.
In addition, the proposed “healing centers” according to some critics, could put public safety at risk and send the wrong message to children.
The move comes a decade after Colorado voted to legalise recreational marijuana, after initially allowing its use for medical reasons.
It has led to a multibillion-dollar industry with hundreds of dispensaries popping up across the state.
However, critics of the latest ballot initiative say the same deep-pocketed players who were involved in legalising recreational marijuana are using a similar playbook to create a commercial market.
They believe eventually recreational dispensaries, for dangerous substances, will be the next stage.
Voters in this week's midterm elections also approved recreational marijuana in Maryland and Missouri but rejected it in two other states.
It signals gradual support for legalisation even in conservative parts of the country.
The results mean that 21 states have approved marijuana's recreational use.
Under the measure, the psychedelics that would be decriminalised are listed as schedule 1 controlled substances under state and federal law and are defined as drugs with no currently accepted medical use with a high potential for abuse.
The FDA has designated psilocybin a "breakthrough therapy" to treat major depressive disorder.
The designation can expedite research, development and review of a drug if it might offer substantial improvements over existing treatments.
Colorado's ballot initiative would allow those 21 and older to grow, possess and share the psychedelic substances but not sell them for personal use.
It also would allow people who have been convicted of offences involving the substances to have their criminal records sealed.
In 2020, Oregon became the first state in the nation to legalise the therapeutic, supervised use of psilocybin after 56% of voters approved Ballot Measure 109.
But unlike the Colorado measure, Oregon allows counties to opt out of the program if their constituents vote to do so.
Oregon's initiative is expected to take effect at the beginning of next year.
Washington, D.C., and Denver have partially decriminalised psychedelic mushrooms by requiring law enforcement officers to treat them as their lowest priority.
