Table 2

Preparations of cannabis (USA and UK)

Form Source THC content (this is extremely variable and the figures are approximate)
References: Mendelson (1987), Gold (1991), Schwartz (1991), Robertson et al (1996), World Health Organization (1997), Hall & Solowij (1998), Solowij (1998).
THC, tetrahydrocannabinol.
Marijuana (USA) Dried leaves/stalks/flowers/seeds
Cannabis (UK)
(Herbal cannabis) Traditional cigarette (reefer) of 1960s and 1970s 1-3% THC (∼10 mg/reefer)
Modern cigarette (joint) of 1980s-1990s; result of intensive cultivation and more potent subspecies (sinsemilla, skunkweed, netherweed and others) 6-20% THC (60-200 mg/joint, over 300 mg if laced with hashish oil)
Hashish (USA) Resin, secreted by plant
Cannabis resin (UK)
Bricks, cakes, slabs 10-20% THC
Hashish oil Product of extraction by organic solvents 15-30% THC (sometimes up to 65%)