"In 2010, a total of 93,732 illicit drug users were treated at outpatient centres throughout Spain. If the same spread as recorded in the treatment demand indicator ('admitted to treatment within the last 12 months') for heroin for that same year (2010) is assumed for this group, we would find 93,732 x 32.4% = 30,369 individuals who had been in treatment for heroin in 2010 and, by applying the multiplier (30,369 x 100/45), an estimate of 67,487 problem heroin users in the population would be calculated.
"Lastly, it must not be overlooked that the previous estimates (38,500 and 67,487) would be, generally speaking, those heroin users who are not in treatment with opioid maintenance (OMT), as these are recorded separately. In 2010, according to the data furnished by the Autonomous Communities, there were 81,022 in OMT. It is known that a none too negligible percentage (around 40%) of the users on OMT additionally use heroin, as a result of which 81,022 x 40% = 32,408 could also be considered problem users.
"Thus, the sum of the aforementioned (32,408) and the estimates previously calculated in parallel (38,500 based on the TDI and 67,487 based on the total number of individuals treated for drug use at outpatient centres) makes it possible to establish a range within which the final estimate of problem users in Spain in 2010 (70,908 and 99,895 individuals) would fall. These figures mark an approximate 3.7% average increase compared to the figures estimated for 2009 included in the 2011 Spanish National Report (68,056-96,624 individuals).
"There is no clear-cut consensus among the experts as to whether those heroin users who are undergoing treatment, regardless of whether or not they are undergoing maintenance treatment, must continue being considered 'problem users'. The inclusion and exclusion-related criteria being used by the different countries to estimating the number of problem drug users vary greatly and are based on widely differing reasons."


Government Delegation of National Plan on Drugs (Reitox National Focal Point for Spain), "2012 National Report (2011 Data) to the EMCDDA: Spain: New Development, Trends and in-depth information on selected issues" (Madrid, Spain: DGPNSD, Dec. 2012), pp. 116-117.