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Cannabis is worth bothering with

In 1990s Britain a common reaction to allocating resources to treating cannabis users was, ‘Why bother? We have more than enough patients with problems with serious drugs like heroin.’ Calls for a treatment response were seen as pathologising what in many societies is both normal and in some ways desirable youth development: trying new experiences, challenging conventions, exposing the hypocrisy of alcohol-drinking adults. The typically calming use of the drug by adults was seen as preferable to the main alternative, alcohol and its associated violence and disorder.

Those views retain some validity for the vast majority of cannabis users, but this has become, and/or become seen more clearly as, a drug with a problem tail which justifies therapeutic intervention. As heroin use and treatment numbers fall way, cannabis treatment numbers are on the rise – not, according to Public Health England, because more people are using the drug, but perhaps because services relieved of some of the recent pressure of opiate user numbers are giving more priority to cannabis, because they are making themselves more amenable to cannabis users, and because stronger strains of the drug are creating more problems.

Cannabis accounts for half of all new drug treatment patients

Patients starting treatment for drug problems for the first time, UK, 2003/04 to 2013. Shows cannabis numbers increasing as opioid numbers fall

Whatever the causes, across the UK figures submitted to the European drug misuse monitoring centre show that the proportion of patients starting treatment for drug problems who did so primarily due to their cannabis use rose steadily from 11% in 2003/04 to 27% in 2013, that year amounting to about 27,270 individuals. Among first ever treatment presentations, the increase was more pronounced, from 19% to 49%, meaning that by 2013 their cannabis use had became the main prompt for half the patients who sought treatment for the first time chart right. Showing that more users was not the reason for more starting treatment, over about the same period, in England and Wales the proportion of 16–59-year-olds who in a survey said that had used cannabis in the past year fell from about 11% to about 7% in 2013/14, having hovered at 6–7% since 2009/10.

The treatment figures largely reflect trends in England, where in 2013/14 the number of patients starting treatment due primarily to their cannabis use had continued to rise to 11,821, 17% of all treatment starters, up from around 7,500 and 9% just seven years before. The greater ‘stickiness’ of opiate use meant that in the total treatment population – new and continuing – the proportionate trends were less steep, cannabis numbers rising from around 11,000 in 2005/06 to 17,229 in 2013/14, and in proportion from 6% to 9%. Among younger adults, cannabis dominates; in 2013/14, far more 18–24s started treatment for cannabis than for opiate use problems – 5,039 versus 3,142 – and they constituted 43% of all treatment starters.

Further down the age range, among under-18s in treatment in England, cannabis is even more dominant. In 2013/14, of the 19,126 young people who received help for alcohol or drug problems, 13,659 or 71% did so mainly in relation to cannabis, continuing the generally upward trend since 2005/06.

Though the crime reduction justification for treating adult heroin and crack users is not so clear among young cannabis users, still immediate impacts plus the longer term benefits of forestalling further problems has been calculated to more than justify the costs of treating under-18 patients, among whom cannabis is the major player.

Cannabis users rarely stay in long-term treatment

Remission rates in US NESARC survey: Shows that cannabis dependence is overcome more quickly than dependence on alcohol or tobacco

Relative to the main legal drugs, at least in the USA dependence on cannabis is more quickly overcome. A survey of the US general adult population found that within a year of first becoming dependent, 3% each of smokers and drinkers were in remission and remained so until they were surveyed. For cannabis the figure was nearly 5% and for cocaine, nearly 9%. After ten years the proportions in remission had risen to 18% for nicotine, 37% for alcohol, 66% for cannabis and 76% for cocaine chart right. About 26 years after first becoming dependent, half the people at some time dependent on nicotine were in remission, a milestone reached for alcohol after 14 years, for cannabis six years, and for cocaine, five.

Unlike heroin users, regular users of cannabis have been seen as sufficiently amenable to intervention to warrant trying brief interventions along the lines established for risky but not dependent drinkers, and sufficiently numerous in some countries to make routine screening in general medical and other settings a worthwhile way of identifying problem users. When the World Health Organization trialled its ASSIST substance use screening and brief advice programme in Australia, India, the United States and Brazil, just over half the identified patients (all had to be at moderate risk of harm but probably not dependent) were primarily problem cannabis users. Among these, risk reduction in relation to this drug was significantly greater among patients allocated to a brief advice session than among those placed on a three-month waiting list for advice. In each country too, risk reduction was greater among intervention patients, except for the USA, where the order was reversed. Suggesting that severity of use was not a barrier to reacting well to brief intervention, only patients at the higher end of the moderate risk spectrum further reduced their cannabis use/risk scores following intervention. The ASSIST study was confined to adults, but young people in secondary schools in the USA whose problem substance use focused mainly on cannabis also reacted well to brief advice.

In some studies brief interventions have been found to work just as well as more intensive treatment, but when the patients are heavily dependent, and the most difficult cases are not filtered out by the research, longer and more individualised therapies can have the advantage. These studies on adults might not translate to adolescents, for whom approaches which address family, school and other factors in the child’s environment are considered most appropriate for what are often multiply troubled youngsters.

The relative persistence of opiate use problems and transitory nature of those primarily related to cannabis seemed reflected in an analysis of treatment entrants in England from 1 April 2005 to the end of 2013/14. At the end of this period just 7% of primary cannabis users were still in or back in treatment compared to the 30% overall figure and 36% for primary opiate users. The figure peaked at 43% for users of opiates and crack. Over half – 53% – of primary cannabis users had left treatment as planned, apparently having overcome their cannabis problems, compared to 27% of primary opiate users and just 20% with dual opiates and crack use problems. Another 40% of cannabis users had left treatment in an unplanned manner not having overcome their dependence, a slightly higher proportion than among opiate users. The figures tell a tale of relatively high level of success which enables cannabis users to leave treatment, though even in the absence of recorded success, few stay long-term.

However, the forms patients in England complete with their keyworkers while in treatment seem to tell a different story. Compared to how they started treatment, around six months later 45% of primary cannabis users were assessed as using just as often (including a few using more), compared to 29% of opiate users and 38% whose main problem drugs were both opiates and crack, suggesting more rapid and/or more complete remission for opiate users than for cannabis users. One interpretation is that the widespread use of substitute drugs like methadone more reliably reduced the illegal opiate use of opiate users and also helped retain them in treatment, while cannabis users tended quickly to leave treatment, having done well or not. However, these figures relate only to patients who completed the forms at their six-month review, which in practice could have happened anywhere from about one to six months after their assessment for treatment. What proportion of primary cannabis users were still in treatment at that point and available to complete the forms is not clear, but they may have been the patients whose problems were deep seated enough to require extended treatment.

These are some of the issues thrown up by a set of patients and a set of interventions rather different from those associated with the drugs treatment in the UK has normally focused on. If current trends continue, understanding the findings of these and other studies will become yet more important to British treatment services.

Last revised 03 March 2015. First uploaded 01 March 2011

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