The Scottish Government

Title

Estimated national prevalence of problem drug misuse in Scotland

National Indicator/Target

To decrease the estimated number of problem drug users in Scotland by 2011

Brief Description

Estimates the numbers of adults (aged 15 to 64) who misuse opiates and/or benzodiazepines (including methadone) in Scotland in 2006.

Previous studies were carried out to estimate prevalence in 2000 and 2003 amongst those aged 15-54 years.

Strategic Objective(s) to Which Indicator Relates

This indicator informs progress in relation to:

· Healthier; Safer and Stronger

More Detailed Definitions

Definitions of Keywords

Problematic drug users: People who can be identified as misusing:

• Opiates (including heroin and methadone)
• Benzodiazepines illicitly
• Cocaine powder problematically
• Crack cocaine

Age range: Estimates for 2006 are based on those between 15 and 64 years of age. Historical estimates (for 2000 and 2003) were for those between 15 and 54 years of age, and a comparable percentage of population figure is provided for the 2006 estimates.

Evidence Source

Estimates have been produced through research commissioned by NHS (NSS) Information Services Division Scotland, using an internationally-recognised capture-recapture methodology.

Data on drug users are collected from:

Clients registering with specialist drugs services

• The Scottish Drug Misuse Database
• Drug Treatment Agencies

Drug-related hospital admissions

• Hospital admissions data

Police detentions under the Misuse of Drugs Act (problem drug users only)

• Scottish Police Forces

Social enquiry reports mentioning drug problem(s) and hepatitis C tests (injectors only)

• Social Enquiry Reports

Injecting drug use

· Hepatitis C Register

The data are analysed to produce estimates of the number of problematic drug users at a variety of geographical levels including:

· Council area

· NHS Board area

· DAAT area

· Police Force area

· Community Health Partnership areas (Glasgow City and Fife)

· Community Justice area.

The estimates are also broken down by age (males only) and gender, as well as the number of injecting drug users, problematic powder or crack cocaine users.

Baseline and Past Trends

Estimates of prevalence in 2006 (published on 06 October 2009) will be taken as the baseline for this indicator.

Table 1: Estimated numbers of problem drug users (opiates and/or benzodiazepines): Scotland 2000, 2003 and 2006.

* Please note the 2006 Scotland point estimate refers to those aged 15-64 rather than 15-54 years in 2000 and 2003. However, the corresponding percentage has been adjusted to show prevalence amongst those aged 15-54 to facilitate comparisons with previous studies.

2006 estimates:

Source: Estimating the National and Local Prevalence of Problem Drug Misuse in Scotland, Centre for Drug Misuse Research, University of Glasgow Scottish Centre for Infection and Environmental Health.

http://www.drugmisuse.isdscotland.org/index.htm

The 2006 study found that:

• An estimated 55,328 individuals were misusing opiates and/or benzodiazepines. This corresponds to 1.62% of the population aged between 15 and 64.
• 30% of problematic drug users were female.
• For males, 24% were aged between 15 and 24, 48% between 25 and 34 and 28% aged between 35-64.
• An estimated 23,933 people were injecting opiates and/or benzodiazepines in 2006.

2003 estimates:

Source: Estimating the National and Local Prevalence of Problem Drug Misuse in Scotland Centre for Drug Misuse Research, University of Glasgow Scottish Centre for Infection and Environmental Health.

http://www.drugmisuse.isdscotland.org/publications/local/prevreport2004.pdf.

2000 estimates:

Source: Estimating the National and Local Prevalence of Problem Drug Misuse in Scotland Centre for Drug Misuse Research, University of Glasgow Scottish Centre for Infection and Environmental Health.

http://www.drugmisuse.isdscotland.org/publications/local/Prevalence.pdf

Methodology

The validity, reliability and precision of any drug prevalence estimation method are important issues. The study employs the 'capture recapture' methodology (involving log-linear modelling). The capture-recapture methodology explicitly models various relationships and dependencies between data sources and to an extent between different genders and age groups. For a given set of data, differing estimates can be obtained and these estimates are evaluated in terms of validity and precision. Statistical techniques have been developed to maximise the validity of capture-recapture methods, such as undertaking sensitivity analyses. The study will use the 'boot-strapping' process to achieve 95% confidence intervals.

For more information on the methodology employed in these studies, please see:

http://www.drugmisuse.isdscotland.org/publications/abstracts/prevalence3.htm

Data Ownership and Quality Assurance

The evidence source is treated by NHS ISD Scotland as an official statistic. The source is a commissioned research project. The ownership of the research materials and of the reports lies with Scottish Ministers.

Methodology for Recent Change Arrow on Scotland Performs

This evaluation is based on: any difference within +/- 2% per annum suggests that the position is more likely to be maintaining than showing any change. A decrease in the rate of 2% per annum or more suggests the position is improving; whereas an increase of 2% or more per annum suggests the position is worsening. The threshold of 2% per annum chosen is based on an assessment of the data available at this time, and may need to be reviewed as more information becomes available in the future.

Publication of Data

The Executive Report, complete with summary, is published on the ISD Scotland webpage:

http://www.drugmisuse.isdscotland.org/index.htm