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Mental health 360: prevalence

Overview

  • Prevalence of mental illness among children and young people has increased since 1999.  

  • National prevalence data for adults is out of date. Recent surveys suggest an increase in prevalence, but lack of data makes it difficult to plan services and preventive interventions. 

  • Prevalence at a population level often masks differences between groups.  

  • Prevalence data needs to be considered within the context and the timing of when it was collected, as many types of mental illness are partly a response to external and societal stresses.  

Prevalence of mental disorders has increased 

Overall, children in England are getting healthier. Between 1999 and 2017 there was an increase in the proportion of children aged 5–15 who are ‘healthy’ (with neither physical nor mental health conditions) and a decrease in the numbers of children with long-term physical health conditions. However, there has been a statistically significant increase in the number of children with mental health conditions. Mental disorders typically first emerge during childhood, adolescence or young adulthood.  

The most recent population survey of mental health in children and young people in England was carried out in 2017. It found that 1 in 8 of those aged 5–19 years had at least one mental disorder. Rates of mental disorders increase with age: 9.5% of 5–10-year-olds experience a probable mental disorder compared with 16.9% of 17–19-year-olds. Data from this survey shows a small increase over time in the prevalence of mental disorders among children aged 5–15, from 9.7% in 1999 to 11.2% in 2017. This increase is driven by a rise in emotional disorders and less-common disorders such as autism.

The prevalence of mental disorders among 5–15-year-olds has increased over time

The Adult Psychiatric Morbidity Survey provides information on the prevalence of a range of psychiatric disorders among adults in England. This survey was last completed in 2014, with a further survey due for publication in 2024. Between 1993 and 2014, the prevalence of common mental disorders increased from 15.5% to 18.9%. This increase was mainly due to more adults reporting symptoms of anxiety (up from 4.4% to 6.6%) and depression (up from 2.2% to 3.8%). There were also notable increases in the prevalence of suicidal thoughts (from 3.8% in 2000 to 5.4% in 2014) and self-harm, which had more than doubled.  

Prevalence of common mental disorders has increased over time

The Covid-19 pandemic had a negative impact on children and young people’s mental health 

Between 2020 and 2023, four surveys were carried out to assess the prevalence of mental disorders among children and young people using a sample of participants from the 2017 national psychiatric morbidity survey. Among children aged 8–16 years, rates of probable mental disorder rose from 12.5% in 2017 to 17.1% in 2020, rising again to 20.3% in 2023. Among young people aged 17–19 years, rates of probable mental disorder rose from 10.1% in 2017 to 17.7% in 2020, rising again to 25.7% in 2022, before falling slightly to 23.3% in 2023.   

Alternative estimates of prevalence are available but more limited 

A number of alternative datasets can shed light on the prevalence of mental disorders among adults but are more limited in the scope of disorders that they cover. 

As part of the Quality and Outcomes Framework, GPs collect data on the number of people with a diagnosis of depression and psychotic disorders, including schizophrenia and bipolar disorder. This data shows that between 2012/13 and 2021/22, there was a consistent increase in the prevalence of depression. The prevalence of psychotic disorders also increased but only up until 2018/19, after which there was no further change.  

Measures of wellbeing within population surveys can also serve as a proxy for understanding changes in prevalence. The Understanding Society’s UK Household Longitudinal Study shows an increase in people reporting symptoms of depression or anxiety from 2014/15 onwards. The Annual Population Survey shows that average ratings of anxiety improved from 2011/12 until 2014/15, remained relatively stable until 2018/19, then deteriorated. Although levels improved in 2021/22, there was another decrease in 2022/23, and average ratings of anxiety remain above pre-pandemic levels.  

Together, these measures indicate increases in the prevalence of depression and anxiety disorders among adults in recent years, exacerbated by the impacts of the Covid-19 pandemic. However, differences in how the data is collected mean that it is of limited use for supporting the planning of health and care services and prevention through public health interventions. 

Some groups are more vulnerable to poor mental health 

The prevalence of mental disorders in the total population masks the fact that people from some groups are both more likely to develop poor mental health and less likely to recover without additional support. The impacts of the Covid-19 pandemic led to a marked deterioration in mean population mental health at the start of the pandemic’s onset, which did not begin improving until October 2020. Undoubtedly, most people experienced negative impacts from Covid-19 and government measures to control the spread of the virus. However, analysis of relevant data shows that some groups of people were unaffected or showed more rapid recovery to pre-pandemic levels of mental health, while others either continued to deteriorate over time or showed consistently poor mental health. The latter groups were more likely to comprise people living in deprived neighbourhoods, of Asian, mixed or Black ethnicity, and those with pre-existing mental health problems.  

Timeliness and quality of prevalence data matters 

The Covid-19 pandemic led to a large number of rapid studies on prevalence of mental health conditions. During the pandemic, three follow-up surveys to the 2017 national psychiatric morbidity survey were conducted that showed a likely increase in the prevalence of probable mental disorders among children and young people. However, a review of studies undertaken during this period that included studies with a wider range of methods and measures indicates a more mixed picture. Whereas some studies showed improvements in mental health, others showed no change or a deterioration. The authors concluded that, as with adults, the effects of the pandemic on children were not universal but depended on the circumstances and context of the children, young people and families involved. Factors such as the timing of surveys (eg, during lockdowns) also mean that findings are especially sensitive to external stresses. This highlights the need for comprehensive, up-to-date prevalence data that can be relied on to plan services. 

Mental health 360: access

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