The drugs unit at the Home Office finally managed a reply to my comments regarding Talk to Frank information sent in April and presented in this blog from May 5th

The reply  did at least address most of my points.

Comments are added throughout:

Home Office:

Thank you for your email dated 16th April where you raise several points that I hope you’ll find covered in this response. Firstly I want to apologise that it has taken until now to get a response to you. I’ve had to coordinate contributions from individuals across the Home Office and Department of Health.

We regularly review the FRANK website to ensure it is fit for purpose.
Information on the FRANK website is based on up-to-date scientific review of the evidence on cannabis, including recent expert reports on the topic by the Advisory Council on the Misuse of Drugs (ACMD).
However, I will address each of your points in order.

First, your letter states that adverts in the media have given the impression that cannabis regularly causes users to be sick and that this is not the case.  The media campaign does highlight unpleasant side-effects that may occur with cannabis use but it does not attempt to indicate exactly how frequent or regular these are.

Talk to Frank adverts over the past year have made great play of the claim that cannabis makes users sick. A recent radio advert was built entirely around the claim (oh sorry mate, got some puke in your hair) and the “party drugs” TV commercial (see it here on the Guardian website) also made a great play of it, there have been others such as the Brain warehouse commercial.

Nausea or sickness may be experienced more often by certain types of user, for example first-time cannabis smokers or in those who use combinations of substances (including alcohol) together. And hence some more experienced users may see some potential effects as less relevant to their experience. You are quite correct that therapeutic forms of cannabinoids can have the effect of reducing nausea and vomiting in certain patients.

They do acknowledge the anti emetic properties of cannabis, yet have often made the claim that “stoners puke”.

Second, you have stated that you know of no research to prove FRANK’s statement that regular cannabis use is associated with the increased risk of developing mental illness and that cannabis does not cause the severe mental illness FRANK appears to be claiming.

The statement made on the FRANK website is based on a careful consideration of the evidence including independent analysis by ACMD of all the available research literature on this topic, and that involved detailed consideration of all the research studies cited in your letter.

There have been a number of studies which claimed to show an association with cannabis use and mental illness, true, but I know of no population based study which has supported the theory of a causal link for people not predisposed to the illness anyway. If it were the case, rates of psychotic illness would have risen greatly over the past 40 years as the use of cannabis grew. No such increase appears to have happened.

It is important not to take single research studies out of context to try and establish a particular point as you appear to have done in quoting the Danish study, to which you appear also to have added your own conclusion.

It is indeed important not to cherry pick research, a point I often make on this blog, however the Danish study  (Familial Predisposition for Psychiatric Disorder) was a big – if not the biggest – real world study into the claims of cannabis induced illness. No scientific study can ever prove anything, at best a positive result can provide evidence a theory is correct. But a negative result is somewhat more convincing in rejecting a hypothesis. The Danish study was such a report.

The only reference I made to the Danish study was to quote it:

However, the results clearly show that cannabis-induced psychoses do not occur randomly. Rather, the degree of hereditary predisposition in individuals who receive treatment of cannabis-induced psychosis closely mirrors that in those who develop schizophrenia with no history of cannabis induced psychosis. The results agree with those of other studies that show that cannabis predominantly causes psychotic symptoms in those persons who are predisposed to develop psychosis or show signs of psychosis in the absence of cannabis use

I can’t see any conclusion of my own that I added.

Home Office continues:

ACMD has concluded that the evidence ‘supports a causal association between the use of cannabis in adolescence, and the later development of schizophrenia’ and that the evidence ‘points to a probable, but weak, causal link between psychotic illness and cannabis use’. ACMD also concludes that ‘In some instances, acute cannabis intoxication appears to precipitate a psychotic state that may continue for some time and require treatment with antipsychotic drugs.’

“probable but weak” is hardly the same as  “known to be associated with an increase in the risk” as they claim on the Frank website.

We strongly reject any suggestion that we have overstated the state of knowledge in this area. Regular, heavy users of cannabis are unlikely just through personal experience to be aware of their increased risk of future problems, and so providing a balanced, objective analysis of the research evidence is particularly important in ensuring individuals have accurate information to make informed choices.

It’s pretty obvious I would still not agree that the claims made on Talk to Frank represent a ” balanced, objective analysis” on the basis of this answer. We’ll agree to differ.

The next bit is very interesting. Regarding the research carried out by researchers ar Keele University for the ACMD review in 2008:

The Frisher and Crome analysis of a fall of prevalence of diagnosed psychoses and fall of prevalence and annual incidence of diagnosed cases of schizophrenia and psychosis in general practice between 1996 and 2005, to which you refer in your letter, was reported by ACMD in its most recent report and was taken into account before coming to its conclusions on this issue.

On your point about making public the results of the Keele study, the Study was commissioned by the ACMD, not the Home Office. However, we understand that a peer reviewed paper by the authors of the Study, based on their findings has just been accepted by Schizophrenia Research for publication.

Sadly thy don’t say when it will be published but Schizophrenia Research is worth keeping an eye on. It will make interesting reading when it is released however, if reports are to be believed it will caste even more doubt on the claims of a causal link between cannabis and mental illness. Interestingly this wasn’t denied in this reply.

Third, you claim that the effects of cannabis are more varied than is reported in the FRANK website and that the withdrawal effects reported on the website, “sweating, shaking and diarrhoea”, is over stated and not associated with cannabis use.

You are correct that the commonly-used broad categorisation of drugs, for example into stimulant, sedative, hallucinogen and sometimes opioid, is necessarily somewhat limited in describing all the specific effects of every drug. However, the approach can provide a useful way of indicating the broad range of effects commonly experienced and is quite widely used. It is also quite true that many drugs categorised as hallucinogens typically present mainly with sensory illusions and distortions or other perceptual changes and much less often with frank hallucinations.

This is true. However the point I was trying to make is that the effects of cannabis vary greatly according to the type or strain and that the description given on Talk to Frank was too narrow.

In regards to the wide range of withdrawal effects described for cannabis, this is consistent with the intended approach of the FRANK website to give accurate information that reflects the research literature. By far the main problem of cannabis dependence is not physical withdrawal symptoms but rather the degree of psychological dependence that can develop in regular users and that can maintain its use in those who are otherwise motivated to stop. However, some individuals on stopping heavy cannabis use have also been reported to have one or more of the withdrawal effects described and it is likely for some this can be an important factor.

This is important because it accepts the claim that withdrawal from cannabis is psychological, not physical in all but the most extreme cases, and to be honest even those are highly questionable. They go on:

The growing research base and consistency of symptoms reported across different studies does suggest that a valid cannabis withdrawal syndrome does occur in a number of users who abruptly stop using cannabis. The number and magnitude of the perceived withdrawal symptoms reported varies between individuals, and whilst some, as you acknowledge, are reported with higher frequency, (e.g. sleep difficulty and strange dreams, anxiety, depressed mood, irritability, restlessness, decreased appetite and weight loss), others (eg, shaking, sweating and diarrhoea) are certainly less often reported. However, we consider that as those less frequent effects have been reported sufficiently in peer reviewed academic journals it does warrant mentioning them. We did though include a reference to their relative infrequency in the wording chosen viz.
‘some may even…’, which does suggest a more exceptional occurrence.

Shaking, sweating and diarrhoea when withdrawing from cannabis, if it happens at all, is going to be extremely rare to the point of being vanishing rare. This is an overstatement, an exaggeration albeit carefully worded.

Finally, on purity you assert that contamination is the direct result of the fact that cannabis is illegal and supplied by an uncontrolled black market and that FRANK needs to make this clear together with other dangers you claim are caused by prohibition.

FRANK’s main health and education message is that those drugs like cannabis, that are controlled under our misuse of drugs legislation, are harmful to health, illegal and should not be taken.

Well, no, that’s not what it claims to be offering. Frank claims to give honest, accurate and trustworthy information about drugs, it doesn’t claim to give a government message – although of course, that is what it does.

Here they drop a real bombshell of an acknowledgement:

We accept that cannabis may be more harmful if it is supplied with dangerous substances that are added by unscrupulous drug dealers who seek to maximise their profit by contaminating the drug. But we also accept that our misuse of drugs legislation imposes responsible controls on the unauthorised supply and possession of this and other illegal drugs and that it will continue to do so.

They accept that their legislation the government is responsible for is creating additional risks to which people – many of them young – are being exposed. Clearly the legislation does not impose any controls because the product remains available and the government is forced to run Talk to Frank as a result. Beyond this, they didn’t mention my point about harm reduction and tobacco smoking.

Of course, the harms of cannabis must be spelt out clearly. The Government’s aim is to ensure that people – and young people in particular – are well aware of all the risks. However, any move towards legalisation or decriminalisation is not on the agenda. It would all too readily be perceived as giving a green light to drug use – and that would encourage supply and use.

Quite why they added that last bit is unclear, I didn’t mention legalisation, only the fact that prohibition prevents control and regulation.

Well, at least they answered me and it only took from 17th April to 15th June – under two months!