Dr Fidelia Cascini, a Forensic Scientist at the University of Rome, has found dramatically increased concentrations of THC in police seizures of cannabis recently. This appears to be a replicated finding across the world. She is about to publish a review of all research on the strength of THC in cannabis from 1970-2009 in the academic journal 'Current Drug Abuse Reviews'. She has found a rise in THC concentration over this time, but a particular jump in more recent years. Previously this had been put down to cultivation techniques, such as indoor intensive growing.