"DCRs have been legally possible in Portugal for almost two decades but have not before been implemented. The overhaul of Portugal’s drug policy is summarized in the 1999 National Drug Strategy, which lays out a shift toward a less repressive drug policy and one centered on humanism, pragmatism, and public health. In 2001, both the decriminalization of low-level possession and use of illicit drugs and the Decree-law 183, regulating harm reduction responses, came into effect. DCRs are among the harm reduction measures detailed.

"DCRs are generally established with the aim of addressing a mix of individual health, public health and public order objectives. These services typically aim to reach out to and maintain contact with the most marginalised populations of people who use drugs — those experiencing high barriers to accessing medical and social support — and to provide a gateway through which these groups can connect with a broader range of health and social support services.

"Drug consumption rooms have been defined as professionally supervised healthcare facilities where people who use drugs can do so in safer and more hygienic conditions (Hedrich et al., 2010). Importantly, they aim to offer hygienic conditions, often supervision by medically trained staff, and a safe environment where people can use drugs without fear of arrest or legal repercussions. DCRs are intended to complement existing prevention, harm reduction and treatment interventions, and are known by various names (see Box 1).

"Drug consumption rooms (DCR) are in place for more than three decades in Europe and have been proven to be effective as a public health response. However, their implementation remains slow and controversial in many countries. In Portugal, despite being legal since 2001, the first DCR only came into reality in 2019 by the initiative of the City Council of Lisbon."

"An entheogen is a psychoactive compound, typically from natural sources such as plants or fungi, that can be used to alter consciousness for spiritual purposes (Johnstad, 2018).

"Psilocybin is a non-addictive classic psychedelic (22, 23) with neuroplasticity-inducing properties (24, 25).

"Methamphetamine is a highly addictive psychostimulant with evidence of neurotoxic properties (1–3) and is consistently ranked as one of the most harmful illicit substances—both to the person using and to society (4, 5).

"There is increasing interest in the use of ketamine as an adjunct to treatment of AUD and management of AWS. There were three studies that showed the benefit of using ketamine as an adjunctive treatment to conventional first-line therapies in patients with severe AWS. Ketamine was added to the medication regimen when AWS was refractory to BZD or after clinical signs of delirium tremens (DT). IV ketamine was administered in variable doses ranging from 0.15 to 0.75 mg/kg/h.

"The potential use of ketamine for AUD was first suggested in 1972 (32, 33).

"The non-negligible non-medical use of ketamine started to emerge in the United States of America in the 1980s, in connection with the rave dance scene, and in Western Europe in the 1990s. Hard data from that period are available only for North America and Western Europe, although the non-medical use of ketamine at alternative dance parties on beaches in Goa, India, in that early period has also been reported.¹¹¹