Mental and Physical Health - an important interrelationship

2019 saw the publication of an ambitious vision for making England the best place in the world to grow old – by Public Health England and the Centre for Ageing Better.

However, achieving this will mean addressing the many factors influencing people’s health throughout their lives, including the inter-relationship between mental and physical health. For example, the King’s Fund reports that:

  • Around 30 per cent of all people with a long-term physical health condition also have a mental health problem, most commonly depression/anxiety
  • People with severe mental illnesses also have significantly higher rates of physical illness 


Inequalities in life expectancy 

People with mental health problems – particularly the most severe mental illnesses – are at much higher risk of a range of physical health conditions. For instance, life expectancy for people with bipolar disorder or schizophrenia is 15 to 20 years below that of the general population, largely as a result of higher rates of cardiovascular disease and other physical health conditions. This disparity in life expectancy is larger than for race, ethnicity, geography or socioeconomic status.


Age based differences 

In 2013, the Chief Medical Officer reported that 50% of mental illness in adult life (excluding dementia) starts before age 15 and 75% by age 18. While some studies have suggested a lower proportion by these ages it is generally accepted that most adult mental health disorders have their roots in childhood and adolescence.

Research published in 2020 highlighted how adversity in childhood is linked to mental and physical health problems throughout life.

Interventions early in life should therefore include implementing evidence-based policies to optimize children’s diet and nutrition, physical activity and cognitive development. For instance wide ranging research shows a strong association between more years of education and living longer. Linking and enhancing preventive child health and education initiatives early in life are key to successful intervention. This needs to be done at the appropriate level in the health and education systems, with community health workers and pre-schools engaged at an earlier stage and with public health programmes including parent training initiatives.


Gender related differences 

The gender health gap in the UK is the widest of all G20 countries. This is leading the government to plan a Women’s Health Strategy.

Gender-based differences include mental health. For example, it is reported that women between the ages of 16 and 24 are almost three times as likely (26%) to experience a common mental health issue as males of the same age (9%).


Impact of diet on mental health 

As is well-known, diet has important physical health implications, for example in relation to the risk of obesity and type 2 Diabetes. However, it also seems to have mental health implications. For example, a 2020 review of published studies concluded, ‘A diet that protects against depression should consist of vegetables, fruits, fibre, fish, whole grains, legumes and less added sugar, and processed foods’.

While research with young adults, published in 2021, found a significant association between ‘junk food’ and depression and anxiety.


Impact of physical activity on health

Exercise is a miracle cure, according to the Academy of Medical Sciences, with regular exercise having the potential to prevent dementia, type 2 diabetes, some cancers, depression, heart disease and other common serious conditions – reducing the risk by at least 30%. This suggests it reduces the risk of both physical and mental illness

As regards mental health more generally, a large study in the US, with data from 1.2 million people, found that individuals who exercised had 43.2% fewer days of poor mental health during the month studied than individuals who didn’t exercise. 

Similarly, research suggests that walking groups don’t just promote physical health, including a reduction in blood pressure and cholesterol levels. They can also reduce symptoms of depression.


Underestimating the physical health needs of people with mental illness

Research suggests that people with mental health conditions are less likely to receive health promotion interventions such as smoking cessation support, and most mental health professionals do not feel that reducing smoking is within their remit , while people with severe mental illnesses are less likely to receive many other forms of preventive care, such as routine cancer screening and immunization. People using mental health facilities are significantly less likely than the general population to be registered with a GP and are more likely to present late with physical symptoms


 Impact of lifestyle on dementia risk

Two long-term studies, reported in 2020, concluded that a healthy lifestyle is associated with a substantially lower risk of Alzheimer’s – an important point when considering health in later life. A healthy lifestyle was defined as not smoking, moderate/vigorous physical activity, light to moderate alcohol consumption (as opposed to heavy consumption), a high-quality diet (e.g. a Mediterranean Diet) and engagement in late-life cognitive activities – the last point indicating the value of mental as well as physical activity.


Case study: Fit as a Fiddle

Fit as a fiddle is a country-wide initiative run by Age UK that championed good mental wellbeing and healthy lifestyles based on the needs of older people locally. Interventions aimed to include BAME communities as well as older individuals with specific disabilities or health risks (e.g. high blood pressure) and those living in deprived areas of the country. Results of the intervention from those responding showed that:

 •60% had undertaken physical activity or exercise  

•35% had undertaken a healthy eating activity  

•2% had completed volunteering or mentoring activity

This example indicates the value of community-based, preventative action, including the role of the voluntary sector, rather than seeing people’s health as being just what the NHS is concerned with. As a former Chief Executive of the NHS described in the title of his 2020 book, ‘Health is made at home, hospitals are for repairs.’

This is a point the government has begun to recognize, for instance with its support for social prescribing – where GPs and other health professionals are prescribing different types of mental, physical and social activity, often arranged through local voluntary organisations or community groups, rather than relying purely on medication.


The importance of integrating care for physical and mental health

The potential inter relationship between mental and physical health suggests the value of a holistic approach, rather than considering each in isolation. This will be an important contribution to encouraging health throughout people's lives and enabling healthy ageing. For example: 

  • More focus is needed on preventing childhood adversity for those most at risk and encouraging children's education and cognitive development, to enhance both physical and mental health outcomes across the lifespan. 
  • More broadly, close partnership between health and education providers, local authorities, voluntary organisations and (where feasible) businesses will help address the social determinants of health, not least for those most at risk of both severe mental and physical illnesses.   
  • Where people have long term physical health conditions the increased risk of mental health problems should be taken into account when providing treatment and support.
  • Conversely, where people have long term mental illness, their treatment and support should ensure that the increased physical health risks are not ignored and that physical health symptoms are taken seriously and not simply attributed to their mental illness.


Denis Duagi and Sara Meriouma. March 2022