Another drug in the serotonergic hallucinogen class is mescaline. This is an alkaloid found in cacti, including the peyote cactus, with traditional use by native populations in North America.^27,29

Mescaline (3,4,5-trimethoxyphenethylamine) acts on a number of different receptor types including serotonin 5-HT_2A/2C, dopaminergic D1/2/3 and adrenergic α1A/2A receptors. Hallucinogenic effects are mainly due to 5-HT receptor stimulation, and being a phenethylamine means it has stimulant activity like amphetamine or MDMA.^27,29

Known for its visual hallucinations, higher doses can also induce changes in perceptions of time, space and personality, hypersensitivity to noise and paraesthesia. Other effects include mydriasis, and elevated blood pressure, body temperature and pulse rate. Nausea and vomiting may occur with higher doses over 200mg, possibly due to its bitter taste. It is regarded as relatively safe to consume with most intoxications being mild and easily treatable.²⁹

Research suggests that among mescaline’s potential uses are in treating alcoholism and improving mental wellbeing in depression, anxiety and substance misuse. A survey of in 2021 has found that among 452 mescaline users there was a self-reported improvement in 86% of people with depression, 76% in alcohol misuse/use disorder, and 68% in drug misuse/use disorder.^29,30

However, research on mescaline is still limited, so it may be some time before it appears in the authorised medicines pipeline.