Commonly used measures for understanding mental health symptoms and substance use in adults

This collection of web pages describe the commonly used measures for understanding mental health symptoms and patterns of substance use in adults in the community. It does not include information on outcome measures used in services. It focuses on common diagnostic and screening measures that are being used or have been used before in Aotearoa New Zealand. The aim of this information is to help people better understand reported information on mental health challenges and problematic substance use. This is important because:

• caution is needed when interpreting reported rates of mental health challenges or problematic substance use included in reports, the media, and from other sources due to the different types of measures used which are not necessarily comparable
• knowing what measure is used can help to work out what is being measured and the strengths and limitations of the information
• robust and accurate information is crucial to planning the range of supports and services needed now and in the future.

We recognise that people experiencing mental health challenges and substance use disorders have a diverse range of strengths, not defined or limited by their symptoms or diagnosis. We acknowledge that discussing measurement instruments that focus on symptoms and diagnoses can be deficit-focussed and this can be viewed as a limitation of commonly used measures. We strive to use person-centred and strengths-based language wherever possible.

Epidemiology is the study of the frequency, patterns, causes, and factors associated with health and disease in a population. This information helps to shape policy, investment decisions, and practices to support wellbeing.

Psychiatric epidemiology is the study of the frequency and pattern of mental health conditions and substance use disorders in a population, to better understand factors associated with their onset and course.

Prevalence refers to the number of people who have a specific condition (that is, meet diagnostic criteria) within a given time frame, within a given population.

Epidemiological measures are measurement tools containing a series of questions or items that aim to better understand health experiences of people in a given population, such as mental health or substance use in Aotearoa New Zealand.

These terms can be found through the descriptions of the measures listed here.

A range of measures have been developed that ask people about their mental health or substance use.

There are three key types of measures:

• Interview schedules or diagnostic measures aim to measure the prevalence of conditions through a series of structured questions. These measures look at whether people meet specific diagnostic criteria (ICD-10 or DSM-IV/5) for a mental health condition or substance use disorder.
• Symptom scales or screening measures identify symptoms of mental health conditions and problematic substance use based on responses to a list of questions. People’s responses are given a value and each value is added to provide an overall score. People experiencing symptoms do not necessarily meet diagnostic criteria for a mental health condition or substance use disorder. Mental health symptoms and substance use may not be having a significant impact on a person’s life, be situational, or transitory.
• General wellbeing measures look at wellbeing more holistically and often include broad questions about a person’s life including their happiness, quality of life, and welfare. The tools used to measure wellbeing are broad and varied as wellbeing encompasses multiple dimensions, including mental health and substance use.

The measures described below use responses from individual people to better understand people’s experiences. Te Pou and the Department of MIHI are also exploring measures that consider whānau or collective experiences of mental health challenges and problematic substance use.

The following measures are those that people might commonly see or hear about when reading information and reports about mental health and substance use in the population. Each card contains basic information with a link to more information.