Creighton, John – In his volume Coins and Power in Late Iron Age Britain (2000), Creighton draws on neuropsychological analyses of rock art to argue that the geometric and distorted anthropomorphic imagery on Iron Age (Celtic) coinage may be derived from altered state of consciousness experiences, possibly influenced by entheogenic plants such as the opium poppy, cannabis, or henbane, for which there is some archaeological evidence in Northern Europe. He goes on to suggest that altered consciousness and coin production were agentic in the negotiation and contestation of power, among Druids, for instance, with the coin—its colour, precious metal composition, indication of status, mythological imagery, and so on— beguiling those who came into contact with it. Imagery on coins, visionary or otherwise, might be deemed too limited in content, and the coins themselves too diminutive, for such an analysis to be reliable. Creighton’s interpretation of the basketry compass work of the Latchmere Heath mirror in a similar light—mirrors offering passages to other worlds—is perhaps more convincing. There is scope for this data to be considered alongside other sources in order to grasp the likelihood of “Celtic shamanisms.” Creighton is positive about the likelihood of finding residues of entheogens in British prehistoric contexts and the insights this might provide into prehistoric religions.
Historical Dictionary of Shamanism by Graham Harvey and Robert J. Wallis 2007