2019-20 Irish National Drug and Alcohol Survey

Data Collection Type
National surveys

Health Research Board (HRB)- Evidence Centre.

Year established


Statement of purpose

The National Drug and Alcohol Survey (NDAS) collects information on alcohol and tobacco consumption and drug use among the general population in Ireland. It also surveys people’s attitudes and perceptions relating to tobacco, alcohol, and other drug use and records the impact of drug use on people’s communities. The 2019–20 NDAS collected information from 5,762 people aged 15 years and older across Ireland.

Out of scope: health status, treatment interventions, prescribed medications apart from sedatives tranquillisers and pain relief.

Coverage (geographical and temporal)

Prevalence estimates are calculated at a national level and for the 10 Regional Drug and Alcohol Taskforce (RDATF) areas at a later stage.

Data collection start February 2019.
Data collection finish March 2020.


The survey used stratified and multistage area probability sampling methods to select a representative sample of the Irish population that was aged 15 years and older and was living in private households. The primary sampling frame was An Post/Ordnance Survey Ireland’s GeoDirectory, a complete database of every building in the Republic of Ireland. Each of the 2.2 million addresses contained in GeoDirectory includes an accurate standardised postal address, usage details for each building (commercial or residential), a unique 8-digit identity number, Eircode, and geo-coordinates which accurately locate the centre point of each building to within one metre.
The sample needed to sufficiently large and structured to provide national estimates of drug use prevalence and estimates for RDATF area. It was calculated that 650 completed interviews in each of the 10 RDATF areas would be required.
A three-stage process was used to construct the sample for this survey. Stratification techniques were used to select primary sampling units (PSUs). In this survey, electoral divisions (EDs) were defined as PSUs. In this survey, EDs were defined as PSUs. In the first stage of stratification, the number of addresses for each RDATF was agreed at between 980 and 1,344.
In the second stage of stratification, 421 PSUs were randomly selected. These PSUs were then ranked by sociodemographic indicators (degree of urban/rural respondents and proportion of owner occupiers) to ensure that a representative cross-section of areas was included. In this way, PSUs of all sizes and compositions would have an equal chance of selection. Twenty-eight addresses were chosen randomly selected from each of the randomly selected 421 PSUs. A household was defined as a person, or as a group of people who normally live at the same property and who share a living room or at least one meal a day. In properties with multiple households, one was randomly selected using a Kish grid. Individuals (aged 15 years and older) within each selected household were randomly selected to take part in the survey. This was done by listing all individuals’ aged 15 years and older living in the household and then randomly selecting one using the CAPI device.

Data users

Policy makers; service providers in drug treatment, harm reduction and prevention; researchers; general public.

Data content

The data collected provide:
A profile of tobacco use, including e-cigarettes, in Ireland
A detailed description of drinking patterns (including hazardous drinking patterns) in Ireland, and the harms associated with alcohol use
Prevalence estimates of lifetime, last year, and last month use of illegal and prescribable drugs
A description of drug use according to sex, age, and area deprivation level
An estimation of the prevalence of alcohol use disorder and cannabis use disorder
Findings on the perceptions and attitudes of people in Ireland towards tobacco, alcohol, and drug use, and
Information on the impact of drug use on local communities.

Data dictionary


National-level identifier variables


Equity stratifiers

Marital status
Living situation
Number of children
Employment status
Benefits/allowances in receipt of
Employment type
Social class
Highest level of education completed.

Data collection methodology

The survey data were recorded face-to-face in respondents’ homes using the Computer-Assisted Personal Interviewing (CAPI) technique. The HRB commissioned Ipsos MRBI to undertake data collection.

The survey has been repeated every four years since 2002. The previous four surveys were carried out in 2002/03; 2006/07; 2010/11; 2014/15.

Clinical coding scheme

AUD alcohol use disorder

AUDIT-C Alcohol Use Disorders Identification Test–Concise

CUD cannabis use disorder

DSM-5 Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition

DSM-IV Diagnostic and Statistical Manual of Psychiatric Disorders, Fourth Edition

HED heavy episodic drinking

M-CIDI Munich-Composite International Diagnostic Interview

Size of national collection

Survey undertaken every 4 years. Approximately 6,000 records created per survey.

Publication frequency

Every four years.

Accessing data

On www.drugsandalcohol.ie website.

Open data portal access


Email contact
Telephone contact