Drug-related deaths in Scotland in 2008

2 Data sources

2.1 The General Register Office for Scotland (GROS) holds details of all deaths which are registered in Scotland. By convention, deaths are counted on the basis of the calendar year in which they are registered rather than the year of occurrence (as the latter might not be known). GROS closes its database for a calendar year around the end of the following June, so the statistics for 2008 are based upon the information which GROS had obtained by June 2009. GROS classifies the underlying cause of each death using International Classification of Diseases (ICD) codes, based on what appears in the medical certificate of the cause of death together with any additional information which is provided subsequently by (e.g.) certifying doctors, the Crown Office, pathologists or Procurators Fiscal.

2.2 Drug-related deaths are identified using details from the death registrations supplemented by information from a specially-designed questionnaire, which is completed by forensic pathologists. GROS requests this information for all deaths involving drugs or persons known, or suspected, to be drug-dependent. Additionally, GROS follows up all cases of deaths of people where the information on the death certificate is vague or suggests that there might be a background of drug abuse. A copy of the questionnaire used in 2008 is in Annex D. This enhancement to the data collection system was described in a paper published by GROS in June 1995 (see Annex C: References).

2.3 The questionnaire was revised for 2008, in order to collect more complete information about the substances present in the body. This caused a break in the series of figures for "drugs reported". The discontinuity arose because:

pre-2008, the form asked about the "principal drug or solvent found in a fatal dose" and about "any other drugs or solvents involved in this death" - so some pathologists reported only the substances which, they believed, contributed directly to each death;
now the form asks about the drugs or solvents "implicated in, or which potentially contributed to" the death and about "any other[s] … which were present, but which were not considered to have had any direct contribution to this death" - so some pathologists now report substances which they would not have mentioned previously.

It is thought that this change accounts for most (if not all) of the apparent large increases, between 2007 and 2008, in the figures for (e.g.) benzodiazepines, diazepam and alcohol.

2.4 There may be other differences, between years and/or between areas, in the way in which the information was produced. For example:

technical advances may enable the detection of small quantities of substances that could not have been found in the post-mortems that were performed several years ago;
the range of substances for which tests are conducted may change - e.g. for a number of years, a laboratory did not routinely test for the presence of cannabis (because the view was that, in general, it did not contribute to causing deaths), but now does so more often, because Procurators Fiscal are now more likely to want to know whether the deceased had been using it. More generally, advice is that there is a demand to obtain more complete and thorough toxicology on all cases tested for drugs, which includes fuller examinations for, and hence a greater possibility of finding, more drugs;
pathologists in one area report any findings of benzodiazepines by referring to that group of drugs unless they are sure that only one particular benzodiazepine (e.g. diazepam) was used, so the areas which they serve appear to have low proportions of deaths for which diazepam is mentioned (compared to areas where diazepam is more likely to be reported, and where there are proportionately fewer reports of benzodiazepines as a group).

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