Adult Psychiatric Morbidity Survey: Survey of Mental Health and Wellbeing, England, 2023/4

The Adult Psychiatric Morbidity Survey (APMS), in common with other surveys, collects information from a sample of the population. The sample was designed to represent the whole population of adults living in residential households in England as accurately as possible within practical constraints, such as time and cost. Consequently, statistics based on the survey are estimates, rather than precise figures, and are subject to a margin of error, shown as a 95% confidence interval.

For example, the survey estimate might be 24.1% with a 95% confidence interval of 22.2% to 26.4%. A different sample might have given a different estimate, but we expect that the true value of the statistic in the population would be within the range given by the 95% confidence interval in 95 cases out of 100.

Where differences are commented on in this report, these reflect the same degree of certainty that these differences are real, and not just within the margins of sampling error. These differences can be described as statistically significant implying no more than a 5% chance that any reported difference is not a real one but a consequence of sampling error. Statistical significance does not imply substantive importance; differences that are statistically significant are not necessarily meaningful or relevant.

Confidence intervals are shown for key statistics and trends within this report and in the accompanying Excel data tables. Confidence intervals are affected by the size of the sample on which the estimate is based. Generally, the larger the sample, the smaller the confidence interval, and hence the more precise the estimate.

The APMS 2023/4 data collection methodology was similar to the methodology used in previous surveys in the series (1993, 2000, 2007, 2014). Findings from 2023/4 can be compared to previous years, and thus trend tables are included in this report.

To determine whether differences in prevalence across survey years indicate change over time, confidence intervals were compared for overall and subgroup estimates. Non-overlapping confidence estimates were used to indicate that changes in prevalence over time were significant. In some instances, slightly overlapping confidence intervals might still be significant according to a generated p-value, which provides an alternative indication of statistical significance. In these instances, this is explained in the commentary. This is a cautious but transparent approach to assessing change over time in this report.

Data in trend tables and associated commentary are presented by sex, defined as male or female at birth.

Further details on changes to the APMS 2023/4 methodology can be found in the APMS 2023/4 Methods documentation.

Across the APMS chapters the prevalence of mental health conditions has been converted into estimates of the number of people in the population in England that they represent.

For population size estimates, the prevalence for each year (expressed as a proportion) was multiplied by a scaling factor equal to the total mid-year population estimate for 2022, then multiplied by the proportion of people in the relevant age and sex group in APMS. The mid-year population estimate was adjusted to represent the population living in private households excluding those aged 65 and over living in institutions. Details of the method used to compute the population size estimates are provided in the APMS 2023/4 Methods documentation .

Gender and sex

In this report, results are mostly broken down by gender identity, that is whether participants identified as a man, a woman or another gender identity such as non-binary. This report uses the terms men and women when describing analysis based on gender identity. Those identifying in another way, such as non-binary, are not included as a separate group due to small base sizes and disclosure risk. They are included in totals and in tables without a gender break. Therefore, where data are presented by gender, the combined number of men and women may total less than the number of all adults due to inclusion of other gender identities. The base for all tables that cover the whole population is described as ‘all adults’.

Data in trend tables and associated commentary are presented by sex, defined as male or female at birth and described as male and female in the commentary. The psychotic disorder and autism spectrum disorder chapters also present data by sex (rather than gender) to facilitate analysis of the combined samples from 2007, 2014 and 2023/4.

More information about demographic data collection can be found in the APMS 2023/4 Methods documentation.

Other analysis breaks

Most of the mental health conditions and behaviours covered in these results are analysed by a core set of breaks in addition to gender or sex:

• age
• ethnic group
• employment status
• problem debt
• area-level deprivation (Index of Multiple Deprivation quintile)
• region
• presence of common mental health conditions and limiting physical health conditions

Chapters also include crossbreaks for mental health treatment received and service use. This could be treatment received for any mental health or emotional problem, not necessarily the one covered by the chapter.

More information about analysis breaks and associated definitions can be found in the APMS 2023/4 Methods documentation.

Estimates presented in the text are rounded to one decimal place, which is equivalent to reporting rates per thousand. Population estimates are presented to the nearest two significant figures.

Data within this report have been age-standardised to allow comparisons between groups after adjusting for the effects of any differences in their age distributions. When different subgroups are compared in respect of a variable on which age has an important influence, any differences in age distributions between these subgroups are likely to affect the observed differences in the proportions of interest. For information about the method used, see the APMS 2023/4 Methods documentation.

Data presented in the substantive chapters of this report are weighted to account for likelihood of selection and non-response. Both weighted and unweighted bases are shown in the tables. Where data are age-standardised, the age-standardised bases are presented. Observed and age-standardised bases differ slightly because observed bases include cases with missing data on age and sex, which are required for age-standardisation.

The survey uses a range of tools to assess or screen participants for different mental health conditions. A summary of the measures used for each of the mental health conditions covered is listed in the APMS 2023/4 Methods documentation.

In APMS 2023/4, the term common mental health condition (CMHC) is used in place of common mental disorder (CMD) as the word 'condition' is sometimes felt to be less stigmatising. For further information see the NHS Mental health conditions webpage and Appendix B of the APMS 2023/4 Methods documentation.