Why doctors have a moral imperative [NOT] to prescribe and support medical cannabis...

David Nutt is admirably open about his conflicted expert status. Disconcertingly his factual statements are open to challenge.

In my Australian experience by far the leading indication for medical cannabis is for cannabis addiction, sometimes thinly veiled by a presenting complaint of back pain etc. Dronabinol and nabilone have been available for decades in USA but are not used due to intolerable side effects including sedation, nausea, vomiting and hallucinations.

Worryingly Nutt grossly misstates the evidence on cannabis teratogenesis. Studies in hamsters and rabbits, much of which was also confirmed in rodents, showed high rates of miscarriage, foetal loss and resorption, limblessness, exencephaly, meningomyelocele and multiple malformations. This pattern was recently confirmed by epidemiological surveys of birth defects in both USA 1 and Europe 2 including limblessness, many cardiovascular defects and the multisystem VACTERL syndrome which has been shown to be due to the blockade by multiple cannabinoids (including THC and cannabidiol) of the key embryonic morphogen sonic hedgehog. Indeed a recent European survey of 90 birth defects showed that virtually all could be related to various cannabis metrics and that VACTERL was most strongly correlated of all 2. French areas cultivating large cannabis crops are also experiencing bovine and human babies born without limbs at rates up to 60 times background.

Many cancers have also been implicated with cannabis exposure including testicular cancer, pediatric acute myeloid and lymphoid leukaemias and total pediatric cancer 3-5 which are highly conceptually important as they represent transgenerational and likely multigenerational transmission of heritable genotoxicity and epigenotoxicity.

If one adds the length of the chromosomes implicated in these cancers to the congenital chromosomal anomalies (trisomies and monosomies) 3 with which cannabis is linked one finds that an impressive 1,754 megabases of the 3,000 megabases or 59% of the human genome is directly implicated in cannabinoid genotoxicity.

Eleven lines of evidence support the view than cannabinoid genotoxicity extends to cellular and organismal aging including advanced cardiovascular age, endocrinopathy, mitochondrial inhibition, gross alterations in DNA methylation and inhibition of histone synthesis and post-translational activation, telomerase inhibition and elevated mortality.

The reticence of British physicians to become involved in the current cannabis hysteria is to be applauded especially with the very thin (with few exceptions) evidence base for clinical indications and the increasingly documented and exceedingly concerning cannabis genotoxicity public health trifecta of cancerogenicity, multigenerational teratogenicity and cellular and organismal aging, which, it goes without saying, is completely unsustainable for population health.