Estimating a hidden population: Determining the number of people with opioid dependence in Scotland
Posted on 18 April 2024 by Lee Barnsdale
- Drugs
In our latest blog, Lee Barnsdale, Programme Portfolio Manager in the Drugs Team at Public Health Scotland, discusses the development of a new methodology to estimate the number of people who are dependent on opioids in Scotland and why this is important.
Scotland continues to have the highest drug-related death rate in Europe with 1,051 people dying as a result of a preventable drug overdose in 2022. Using toxicology analysis, we can determine that opioids were potentially implicated in or contributed to the majority of drug-related deaths in Scotland.
Opioids are a group of drugs which are primarily used to treat pain – they include commonly prescribed medications like codeine, synthetic opioids like fentanyl, and ’street’ drugs like heroin. Their regular use can result in tolerance and dependence, requiring increasing doses and leading to withdrawal symptoms when use is abruptly stopped.
Deaths from accidental opioid overdoses can occur due to respiratory depression and this risk increases if opioids are used alongside other drugs like benzodiazepines.
In order to ensure public health actions are well directed to reduce the harms associated with opioids, it’s important to determine how many people are at on-going risk and may require support for their drug problem.
Why do we need to estimate a figure?
Estimating the number of people who are dependent on drugs is challenging as the number of people with opioid dependence can’t be measured accurately through traditional household, online or telephone surveys. Instead, estimates of the number of people with opioid dependence are reliant on statistical models which can quantify the size of the ‘hidden’ group of people who have not been in contact with drug services.
Previous official estimates of drug prevalence in Scotland are no longer considered appropriate due to issues with the availability and completeness of the data available. As a result, Public Health Scotland (PHS), alongside the University of Bristol and Glasgow Caledonian University, were funded by the Scottish Government to establish a new methodology for estimating the prevalence of opioid dependence in Scotland using linked administrative health datasets. This includes anonymised information generated from interactions with public services, such as the NHS.
The number of people with opioid dependence in Scotland
In March 2024, PHS published the first report from this new public health surveillance collaboration, which estimated the number of people with an opioid dependence in Scotland.
We estimated that between 2014 and 2019, approximately 1.3% of the Scottish adult population were dependent on opioids and that this percentage was stable.
The report concludes that the most likely explanation for these changes is that there is an ageing cohort of people in Scotland with problematic opioid use.
People with opioid dependence are at high risk of avoidable drug-related harms (such as overdose poisoning and blood borne viruses like hepatitis C and HIV) and also suffer high rates of illness and death from other health conditions, such as circulatory and respiratory diseases. An understanding of these additional health needs is important when considering future planning of the healthcare service.
The role of stigma
The stigma that prevents people with a drug problem from reporting their problematic use can also prevent them from seeking help for physical or mental health conditions and can contribute to the harms described above.
Drug dependence can occur for a variety of complex reasons, though there is strong evidence of links between inequalities and adverse childhood experiences. We can all help by treating people with compassion and kindness, as well as understanding the reasons that lead people to developing a drug problem in the first place.
View the ‘Estimated prevalence of opioid dependence in Scotland 2014/15 to 2019/20’ report