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Two cases of "cannabis acute psychosis" following the administration of oral cannabis

Bernard Favrat1*, Annick Ménétrey2, Marc Augsburger2, Laura E Rothuizen3, Monique Appenzeller3, Thierry Buclin3, Marie Pin1, Patrice Mangin2 and Christian Giroud2

Author affiliations

1 Unité de Médecine du Trafic, Institut Universitaire de Médecine Légale (IUML), 1005 Lausanne, Switzerland

2 Laboratoire de Toxicologie et Chimie Forensiques (LTCF), Institut Universitaire de Médecine Légale (IUML), Rue du Bugnon 21, 1005 Lausanne, Switzerland

3 Division de pharmacologie et toxicologie cliniques, CHUV, 1011 Lausanne, Switzerland

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Citation and License

BMC Psychiatry 2005, 5:17  doi:10.1186/1471-244X-5-17

Published: 1 April 2005



Cannabis is the most commonly used illegal drug and its therapeutic aspects have a growing interest. Short-term psychotic reactions have been described but not clearly with synthetic oral THC, especially in occasional users.

Case presentations

We report two cases of healthy subjects who were occasional but regular cannabis users without psychiatric history who developed transient psychotic symptoms (depersonalization, paranoid feelings and derealisation) following oral administration of cannabis. In contrast to most other case reports where circumstances and blood concentrations are unknown, the two cases reported here happened under experimental conditions with all subjects negative for cannabis, opiates, amphetamines, cocaine, benzodiazepines and alcohol, and therefore the ingested dose, the time-events of effects on behavior and performance as well as the cannabinoid blood levels were documented.


While the oral route of administration achieves only limited blood concentrations, significant psychotic reactions may occur.