3.1.1 Based on the definition used for these statistics, there were 867 drug-related deaths in 2016, 161 (23%) more than in 2015. This was the highest number recorded since the series of figures began in 1996, and was 446 (106%) more than in 2006, when there were 421 such deaths. The ‘underlying’ increase since 2006 is only slightly smaller when account is taken of the effect on the statistics of changes in the classification of drugs – refer to paragraphs 3.1.4 to 3.1.6.
3.1.2 The figures on the left-hand side of Table 1 sshow that the past ten years have had six rises and four falls in the number of drug-related deaths. The rises have tended to be greater than the falls, and the trend in the number of drug-related deaths has been upwards. Because the statistics show some year to year fluctuations, moving annual averages are likely to provide a better guide to the long-term trend than the change between any two individual years. Figure 1 illustrates this:
3.1.3 Looking at the chart, it is clear that, up to (and including) 2007, the individual years' figures tended to fluctuate around a long-term upward trend, and were generally within the likely range for random statistical year to year variation about the trend. It also appears that:
The chart and the table show that the 5-year moving average rose for many years, suggesting that there was a clear long-term upward trend, and that the figure for 2010 had been unusually low relative to that long-term trend. When the figure for 2013 was obtained, there was a slight fall in the 5-year moving average (from 554 for 2008 to 2012, to 544 for 2009 to 2013), because there were fewer deaths in the year which had entered the calculation (2013, with 527 deaths) than in the year which had dropped out of the calculation (2008, with 574 deaths). However, with 614 deaths in 2014, 706 in 2015 and 867 in 2016, the 5-year moving average has increased again, to 602 for 2011 to 2015, and to 659 for 2012 to 2016. The pattern of rises and falls in recent years meant that there was not much change in the 3-year moving average for several years: its values were 525 (for 2007 to 2009), 535, 538, 550, 564 and 574 (for 2012 to 2014), suggesting at most only a slight upward trend (compared to much more rapid growth in earlier years). Therefore, there was a possibility that the large year-to-year increases and decreases in the period from 2010 to 2014 were fluctuations around the general level of the much more stable 3-year moving average. However, the large rises to 706 deaths in 2015 and 867 deaths in 2016 have increased the 3-year moving average to 616 (for 2013 to 2015) and 729 (for 2014 to 2016), so the trend appears to be clearly upwards.
3.1.4 As mentioned in paragraph 2.9 (and explained in detail in Annex F) the ‘coverage’ of NRS’s standard definition of a drug-related death ‘widens’ every time another drug is added to the list of substances which are controlled under the Misuse of Drugs Act, because all subsequent deaths from poisoning by that drug will be counted as drug-related. Therefore, in order to give more accurate indications of changes and trends, NRS has developed a ‘consistent series’ which is based on the classification of drugs at the end of the latest year covered by the publication. The rightmost three columns of Table 1 show the consistent series’ number of drug-related deaths, and the ‘extra’ deaths (number and percentage) that would be counted as drug-related on that basis.
3.1.5 As will be seen from Table 1, the consistent series’ figures have never been as much as 6% above the number of drug-related deaths on the standard definition (they were 5.6% higher in 2010, and 5.7% more in 2013). It follows that the changes in the classification of drugs have not had a great effect on the overall total number of drug-related deaths. The year-to-year variation in the number of ‘extra’ deaths has not been large, so the consistent series’ patterns (of rises and falls, and of ‘peaks’ and ‘troughs’) are similar to those of the numbers produced by the standard definition.
3.1.6 The most noticeable break in the continuity of the number of drug-related deaths was caused by the change to the classification of tramadol and zopiclone in 2014. The relevant numbers and changes from 2013 are as follows:
Using the consistent series, the increase between 2006 and 2016 is 438, or 102%: only slightly smaller than the rise of 446 or 106% calculated using the standard definition.
3.2.1 As explained in paragraph 2.6, National Records of Scotland (NRS) implemented WHO updates to the coding rules at the start of 2011. This changed the classification of the underlying cause of many drug-related deaths. However, NRS has estimated what the figures for 2011 onwards would have been, had the data been coded using the old rules.
3.2.2 Table 2 shows the number of drug-related deaths categorised by the underlying cause, defined in terms of groupings of the ICD codes. The penultimate row gives the figures for 2016 that were produced by applying the new coding rules: the majority of drug-related deaths (729, or 84%) were coded to ‘accidental poisoning’. This covers the relevant categories within the ICD's section for ‘Accidental poisoning by and exposure to noxious substances’ (for example, it includes ICD-10 code X42 which is defined as 'Accidental poisoning by and exposure to narcotics and psychodysleptics [hallucinogens] not elsewhere classified').
3.2.3 Table 2 also provides NRS's estimates of the figures that would have been produced for 2011 onwards, had the old coding rules been used. On that basis, the underlying cause for the majority of 2016’s drug-related deaths (663, or 76%) would have been 'drug abuse', which covers the relevant categories within the ICD's section for 'Mental and behavioural disorders due to psychoactive substance use'.
3.2.4 Because some of the figures can fluctuate markedly from year-to-year, a better indication of the longer-term changes should be obtained from a comparison of the averages for 5-year periods. These show large percentage increases in deaths for which the underlying cause (on the basis of the old coding rules) was ‘drug abuse’ (from an average of 242 per year in 2002-2006 to an average of 465 per year in 2012-2016) and ‘accidental poisoning’ (from an average of 29 to an average of 101). There was not as much change in deaths caused by intentional self-poisoning (averages of 37 per year in 2002-2006 and 52 per year in 2012-2016) and ‘undetermined intent’ (from an average of 54 to an average of 40).
3.3.1 The NRS database records a wide range of drug combinations (for example in 2006, diazepam was mentioned in almost a fifth of the deaths for which heroin or morphine were reported; and heroin, morphine or methadone were mentioned in over half of the deaths for which cocaine was reported). A complete list of all the substances which were reported to NRS for every death from poisoning (including deaths which are not counted as ‘drug-related’ for the purpose of these statistics) can be found in Table 6.12 of the annual Vital Events Reference Tables, which are available on the NRS website. ‘Unspecified drug(s)’ is recorded in only a small proportion of drug-related deaths (on average, only a couple of per cent per year). Table 3, Table 6 and Table 7 give information on the frequency of reporting of selected drugs, whether alone or in combination with other substances. The drugs listed in these tables are reported in the majority of drug-related deaths (for example, not counting alcohol, at least one of them was reported in 96% of the drug-related deaths in 2000, and in 97% of cases in 2016). The tables show a combined figure for ‘heroin/morphine’ because it is believed that, in the overwhelming majority of cases where morphine has been identified in post-mortem toxicological tests, its presence is a result of heroin use. With effect from the ‘… in 2014’ edition, the tables and text refer to ‘ecstasy-type drugs’ (rather than to ‘ecstasy’ alone), to make clearer what it is that those figures cover: the numbers for 2013 and earlier years are the same as those that were given in earlier editions, but are now described more precisely.
3.3.2 Since these tables record individual mentions of particular drugs, there will be multiple-counting of some deaths (for example if both heroin and diazepam were implicated in, or potentially contributed to, the cause of a death in the latest year, that death will be counted in five of the 'drug' columns of Table 3: ‘heroin/morphine’, ‘heroin/morphine, methadone or buprenorphine’, ‘any opiate or opioid’, ‘any benzodiazepine’ and ‘diazepam’). Therefore, these tables do not give the numbers of deaths that are attributable to each of the drugs mentioned. When more than one drug was reported for a particular death, it may not be possible to deduce, from the information held in the NRS database, which (if any) of them was thought to be the (main) cause of the death, except to the extent that, for 2008 onwards, the database distinguishes between (a) drugs which were implicated in, or which potentially contributed to, the cause of death and (b) any other drugs which were present, but which were not considered to have had any direct contribution to the death. NRS's database has no information about the amounts of each drug that were found, or the possible consequences of taking particular combinations of drugs.
3.3.3 For 2008 onwards, the standard basis for figures for individual drugs is ‘drugs which were implicated in, or which potentially contributed to, the cause of death’ (further information about this is given in Section 2). Table 3 shows that heroin/morphine was implicated in, or potentially contributed to, the cause of 473 (55%) of the 867 deaths in 2016; methadone was implicated in, or potentially contributed to, 362 (42%); one or more opiates or opioids (including heroin/morphine and methadone) were implicated in, or potentially contributed to, 765 deaths (88%); and benzodiazepines were implicated in, or potentially contributed to, 426 (49%). Cocaine, ecstasy-type drugs and amphetamines were implicated in, or potentially contributed to, 123 deaths (14%), 28 deaths (3%) and 25 deaths (3%), respectively. Alcohol was implicated in, or potentially contributed to, the cause of 112 (13%) of the 867 drug-related deaths in 2016.
3.3.4 From Table 3 one can also see that most of the drugs shown have larger figures in 2016 than in any previous year for which the numbers can be compared. The following numbers of deaths for which the specified drugs were implicated in, or potentially contributed to, the cause in 2016 are examples of this:
Although the figure for benzodiazepines more than doubled (from 191 in 2015 to 426 in 2016), the increase in the number for diazepam (which had previously been the benzodiazepine that was most often implicated in deaths) was far less: from 121 in 2015 to 154 in 2016. Most of the rise in the figure for benzodiazepines was due to ‘new’ ones, particularly etizolam and diclazepam, which were implicated in, or potentially contributed to, the cause of death for (respectively) 223 and 72 of the overall ‘benzodiazepine’ figure of 426 such cases in 2016. Etizolam and diclazepam (and some other ‘new’ benzodiazepines) were not controlled under the Misuse of Drugs Act until 31 May 2017, but were subject to the Psychoactive Substances Act when it came into force on 26 May 2016. They are not shown in Table 3 because each was implicated in only single-figure numbers of deaths (if any) before 2014 (etizolam) and 2016 (diclazepam), as can be seen from the slightly larger figures for them (on the ONS/’wide’ basis) that are given in Table Y. Finally, it should be noted that the relatively small numbers for ecstasy-type drugs and amphetamines have had some large percentage year-to-year fluctuations.
3.3.5 It is not possible to make a direct comparison with the figures for 2007 and earlier years because there is a break in the series between 2007 and 2008, due to the revision of the questionnaire which collects information about the drugs found in the body (as explained in paragraphs 2.3 to 2.5). The statistics may also be affected by other differences, between years or between areas, in the reporting of drugs found in the body (examples of which are given in paragraph 2.8). Therefore, apparent changes in the numbers of deaths for which particular drugs were reported must be interpreted with caution, and with the knowledge that there is a clear break in the figures between 2007 and 2008. The change in the method of data collection may have contributed to the apparent large percentage increases, between 2007 and 2008, in the figures for methadone, benzodiazepines generally and diazepam specifically.
3.3.6 Because some of the figures can fluctuate markedly from year to year, the main changes before 2008 are best identified by comparing the averages for 1996-2000 and 2003-2007 (the latter being the final 5-year period before the break in the series). These show that there were marked increases in the numbers of deaths for which there were reports of:
There was not much change in the numbers of deaths for which there were reports of:
It may also be noted that Table 3 in the editions of this publication for 2013 and some earlier years showed that there was a marked fall in the number of deaths for which temazepam was reported (from an average of 47 per year in 1996-2000 to an average of 12 in 2003-2007).
3.3.7 However, while comparing 5-year averages should reduce the effect of year-to-year fluctuations, it will not necessarily give the full picture. In this case, it does not reveal some marked changes during the period:
3.3.8 As mentioned in Section 2, NRS can also produce, for 2008 onwards, figures on the basis of ‘all drugs which were found to be present in the body’, including any other drugs which were present, but which were not considered to have had any direct contribution to the death. The lower half of Table 6 shows figures for 2016 on this basis. There are large percentage differences between the two halves of the table in the figures for benzodiazepines (and diazepam in particular): benzodiazepines were found to be present in the body in the case of 632 of the drug-related deaths in 2016, but had been implicated in, or potentially contributed to, only 426 of those deaths (for diazepam, the equivalent figures are 365 and 154). There are also notable percentage differences between the figures in the two halves of the table for codeine (or a codeine-containing compound), which was found in 80 deaths but was believed to have been implicated in, or to have contributed to, only 43 of them; for dihydrocodeine or a compound thereof (for which the numbers are 150 and 114, respectively) and for alcohol (330 and 112). The figures for heroin/morphine and methadone do not differ much (in percentage terms) between the two halves of the table: these drugs were believed to be implicated in, or to have contributed to, the death in almost every case in which they were found.
3.3.9 Most drug-related deaths are of people who took more than one drug. In such cases, it may not be possible to say which particular drug caused the death. Table 7 shows the numbers of drug-related deaths for which only one drug was reported, which are the minimum numbers of deaths which may be wholly attributable to the specified drugs. The top half of the table shows that there were 66 deaths for which only one drug (and, perhaps, alcohol) was found to be present in the body: with a few possible exceptions (the footnote to the table gives further details), these deaths will be wholly attributable to the specified drug (or, perhaps, to that drug in combination with alcohol). These numbers are all small, when compared to the total number of drug-related deaths: there were 14 deaths for which the only drug reported was heroin/morphine; four deaths for which only methadone was mentioned; one for which only codeine (or a codeine-containing compound) was reported, four for which dihydrocodeine (or a dihydrocodeine-containing compound) was reported, three deaths for which only a benzodiazepine was reported; five deaths for which only cocaine was reported; six deaths for which only an ecstasy-type drug was reported; and three death for which only amphetamines were reported. Information from NRS's database (which does not appear in any of the tables) shows that 10 of the 14 remaining ‘only one drug (and, perhaps, alcohol)’ deaths were due to ‘unspecified drug’; in case of the other deaths, the only substances reported were pentobarbitone (two deaths) and zopiclone (two deaths). In total, there were 16 deaths for which alcohol was mentioned along with only one drug.
3.3.10 The lower half of Table 7 shows deaths for which only one drug (and, perhaps, alcohol) was implicated in, or potentially contributed to, the death. The numbers here are larger, because this part of the table includes deaths for which other drugs were mentioned as being present but were not considered to have had any direct contribution to the death. So, for example, the figures for methadone are the numbers of deaths for which only methadone (and, perhaps, alcohol) was implicated in, or potentially contributed to, the death - any other drugs (such as diazepam) which were found to be present in the body were not considered to have had any direct contribution to the death. There were 77 deaths for which heroin/morphine was the only drug which was believed to have been implicated in, or to have contributed to, the death; 23 deaths for which methadone was the only such drug; 11 deaths for which dihydrocodeine (or a dihydrocodeine-containing compound) was the only such drug, 19 deaths for which cocaine was the only such drug, and 35 deaths for which alcohol was implicated in, or potentially contributed to, the cause of death, along with one drug. Apart from ‘heroin/morphine, methadone or buprenorphine’, ‘any opiate or opioid’ and ‘any other drug’, the numbers for each of the other individual drugs that are shown in the table are all in single figures, so there were very few deaths which were believed to be due solely to one of those particular drugs alone.
3.3.11 In the lower half of Table 7, the sum of the figures for ‘any opiate or opioid’ (which includes heroin/morphine, methadone, buprenorphine, codeine, dihydrocodeine and compounds containing them), benzodiazepines, cocaine, ecstasy-type drugs and amphetamines is 167, or 19% of the total of 867 drug-related deaths in 2016. This means that one of these drugs was the only drug which was implicated in, or potentially contributed to, the cause of almost a fifth of all drug-related deaths in 2016. There were also 20 deaths for which a drug which is not shown in the table was the only drug which was implicated in, or potentially contributed to, the cause of death. Information from NRS's database (which does not appear in any of the tables) shows that they included four cases where that drug was pentobarbitone, two cases where it was zopiclone, four cases where it was a drug that was responsible for only one such death (the substances reported being amitriptyline, fluoxetine, MXP and quetiapine), and 10 cases where it was ‘unspecified drug’ (alcohol was also implicated in some of these deaths). Therefore, there was a total of 187 cases (22% of all drug-related deaths) where only one drug (plus, perhaps, alcohol) was believed to have been implicated in, or potentially contributed to, the cause of death.
3.4.1 Table 4 shows that males accounted for the majority (592, or 68%) of the drug-related deaths in 2016. This was the case throughout the past two decades, although the precise balance between the sexes has varied from year to year. For example, between 2008 and 2013, the number of male drug-related deaths dropped (from 461 to 393, having been as low as 363 in 2010) whereas the number of female deaths rose (from 113 to 134, having fallen back slightly from 165 in 2012) so the male percentage fell from 80% to 75%. Comparing the averages for 2002-2006 and 2012-2016, to reduce the effects of year-to-year fluctuations on the figures, the percentage increase in the number of drug-related deaths was greater for females (169%) than for males (60%).
3.4.2 From 2003 to 2014, of the age-groups shown, the largest number of drug-related deaths were among 25-34 and 35-44 year olds: using the averages for 2012-2016, 166 out of 659 deaths (25%) were of 25-34 year olds and even more were in the 35-44 age-group (234, or 36%). However, recent years have seen large percentage increases in drug-related deaths in the 45-54 age-group. In 2016, there were 327 drug-related deaths of people aged 35-44 (representing 38% of that year’s total number of drug-related deaths), 213 of 45-54 year olds (25%) and 199 in the 25-34 age-group (23% of the total). In addition, 42 people aged 15 to 24 died (5%), as did 66 in the 55 to 64 age-group (8%) and 20 people who were 65 or over (2%). There are very few drug-related deaths aged 14 and under. The table shows that the number of deaths in a particular age-group can fluctuate markedly over the years (for example, the number of 15 to 24 year olds who died was 100 in 2002, 47 in 2005, 94 in 2007, 65 in 2010, 32 in 2013, 46 in 2014 and 30 in 2015). However, some clear trends can be seen. Comparing the averages for 2002-2006 and 2012-2016 (to reduce the effects of year-to-year fluctuations on the figures), there have been large percentage increases in the number of deaths of 35-44 year olds (from an average of 104 per year in 2002-2006 to an average of 234 in 2012-2016) and people aged 45-54 (from an average of 35 to an average of 157); the number of deaths of 25-34 year olds rose less markedly (from an average of 134 to an average of 166). Deaths of people aged 55 to 64 rose (from an average of 9 to an average of 47), and there was a fall in the number of people aged under 25 who died (from an average of 75 to an average of 39).
3.4.3 Changes in the ages of drug-related deaths can also be seen from the values of the lower quartile age at death (a quarter of drug-related deaths were of people of this age or under), the median age at death (half the deaths were of people of this age or under) and the upper quartile age at death (a quarter of the deaths were of people of this age or older), which appear in the table:
The median is used (rather than the average) because it should be affected less by any unusually high (or low) values.
3.4.4 The lower part of Table 5 shows that, when the underlying cause of death is determined using the old coding rules, 481 (81%) of the male deaths in 2016 were of known or suspected drug abusers compared to 182 (66%) of the female deaths. Of the 86 deaths aged 55 and over, only 32 (37%) were of people who were known, or suspected, to be drug-dependent. The table also provides a more detailed breakdown of the numbers by age-group for each sex.
3.4.5 Table 6 provides information about the ages and sexes of people who died having taken various drugs (perhaps more than one of the substances listed in the table, and maybe other drugs as well). The top half of the table provides figures on the standard basis: ‘drugs which were implicated in, or potentially contributed to, the cause of death’. As mentioned earlier, men accounted for 68% of all drug-related deaths in 2016. Where the drugs listed below were implicated in, or potentially contributed to, the cause of death, men accounted for the following percentages of the deaths:
There were some differences between the distributions by age of people for whom the drugs listed in Table 6 were implicated in, or potentially contributed to, the cause of their deaths. For example, the under 25s accounted for 36% of (the relatively small number of) deaths in which an ecstasy-type drug was implicated, or to which it potentially contributed, compared with only 5% of all drug-related deaths. In addition, 29% of the 123 ‘cocaine’ deaths were of people who were aged 25-34, compared with 23% of all drug-related deaths. About 50% of the 114 ‘dihydrocodeine’ deaths were of people aged 45 and over, compared with 34% of all drug-related deaths.
3.4.6 The lower part of Table 6 provides figures for all drugs which were found present in the body, including those which were not considered to have had any direct contribution to the death. Women accounted for 32% of all drug-related deaths in 2016, but for only 27% of the deaths for which heroin/morphine were found, just 22% of deaths for which cocaine was found, and only 10% of the 30 deaths for which ecstasy-type drugs were found.
3.4.7 The top half of Table 7 gives the numbers of deaths for which only one drug (and, perhaps, alcohol) was found to be present in the body. The numbers are all relatively small, so there is little that can be said about the ages and sexes of the people involved. The bottom half of the table shows deaths for which only one drug (and, perhaps, alcohol) was implicated in, or potentially contributed to, the death. Paragraph 3.3.10 explained why these numbers are larger. However, only for heroin/morphine (77 deaths) might the figures for a particular drug be large enough for analysis of the ages and sexes of the people involved. The main point to note is that females accounted for 24% of all deaths in 2016 for which only one drug (and, perhaps, alcohol) was implicated in, or potentially contributed to, the cause of death, but for only 17% (13 out of 77) of the cases where heroin/morphine (and, perhaps, alcohol) was the only drug which was implicated in, or potentially contributed to, the cause of death.
3.4.8 Table 8 provides drug-related death rates per 1,000 population for a number of age-groups, and shows how these have changed, from 2000 to 2016. For much of that period, the drug-related death rate per 1,000 population was highest for people aged 25-34: it was 0.27 in 2016 and averaged 0.24 over the latest five years (from 2012 to 2016). However, the rate for 35-44 year olds was higher in 2011 and every year since, was 0.49 per 1,000 population in 2016, and its latest 5-year average was 0.35. In recent years, there has been a large percentage increase in the rate for 45-54 year olds: it was 0.27 in 2016 and had a latest 5-year average of 0.20. For the 15-24 age-group, the rate per 1,000 population has latterly been much lower: it was 0.06 in 2016 and averaged 0.06 over the latest five years. The rate for 55-64 year olds has never been more than 0.10 per 1,000 population. Since 2000, there have been increases in the rates for all the age-groups apart from 15-24 year olds, whose rates have tended to decline (with some year-to-year fluctuations).
3.5.1 The drug-related death rates per 1,000 population (shown in Table 8) are based on the size of the whole population of each age-group, the vast majority of whom do not use drugs. Therefore, those figures do not indicate the likely death rate for people who use drugs. Drug-related death rates for the part of the population whose put their lives at risk by using drugs can be calculated using the numbers of problem drug users (age 15-64) that are estimated by the Information Services Division (ISD) of NHS National Services Scotland. The latest such estimates, for the 2012/13 financial year, are available from the ISD website. For the purpose of ISD's estimates,’problem drug use’ is defined as the problematic use of opiates (including illicit and prescribed methadone use) and/or the illicit use of benzodiazepines, and implies routine and prolonged use (as opposed to recreational and occasional use). It follows that ISD's estimates will be smaller than the total number of people who used illicit drugs at some time during the year.
3.5.2 Table 9 shows ISD's estimates of the number of problem drug users in 2012/13 along with the annual average number of drug-related deaths for 2011-2015 (rather than the annual averages for 2012-2016, because they would be less comparable with ISD’s estimates for 2012/13). The first two figures on the first row show that Scotland had 602 drug-related deaths (of all ages) per year (on average) between 2011 and 2015, and an estimated 61,500 problem drug users (aged 15-64) in 2012/13. Combining those figures gives an annual average of 9.8 drug-related deaths per 1,000 problem drug users. The difference between the coverage of the two figures (‘all ages’ for deaths; ‘15-64’ for problem drug users) should not matter much, as Table 4 showed that there are relatively few drug-related deaths of people aged 0-14 or 65+.
3.5.3 Using ISD's estimates of the numbers of problem drug users by age and by sex in the same way, it appears that the annual average drug-death rate (per 1,000 problem drug users) is higher for males (10.0) than for females (9.2), and increases with age (4.0 for problem drug users who are aged 15-24, 7.6 for 25-34 year olds, and 13.0 for those aged 35-64). For each sex, the death rate clearly rises with age, though it should be noted that ISD did not consider the estimated numbers of female problem drug users broken down by age to be sufficiently reliable for publication.
3.5.4 The ISD publication explains that the estimates are produced by combining data from a number of sources, and provides ‘95% confidence intervals’ to indicate the likely margins of error in some of the figures. For the estimated total number of problem drug users for 2012/13, the 95% confidence interval is from 59,900 to 63,300 (or roughly +/- 3%). The values of the lower and upper ends of the confidence intervals can be used to calculate a likely range for the drug-related death rate. Dividing the annual average of 602 drug-related deaths by the value at the upper end (63,300 problem drug users) givers a minimum for the drug-death rate of 9.5 per 1,000 problem drug users; dividing by the value at the lower end (59,900 problem drug users) gives a maximum for the drug-death rate of 10.1 per 1,000 problem drug users.
3.5.5 ISD did not calculate 95% confidence intervals for its estimates of problem drug users broken down by age and sex, but one would expect them to be wider (in percentage terms) for the smaller sub-groups of the population (that is generally the case for the 95% confidence intervals for NHS Board and council areas in Tables HB5 and C5).