Mental and physical health are inextricably linked
Evidence that there is a strong relationship between mental and physical health has been accumulating over the last few decades. This challenges firmly held attitudes and beliefs in both health care and public health about the mind-body dichotomy (1) (2) in which mental and physical health are seen as separate. Further progress on the physical aspects of public health is likely to depend on changing these attitudes and beliefs, and the development of new interventions and programmes which take this evidence into account.
Mental health problems precede physical illness
Mental health problems have increasingly been shown to precede, and be important in the recovery from, physical health problems. For example, the Whitehall Study showed that emotional health, especially negative affect – a general tendency to report ‘distress, discomfort, dissatisfaction, and feelings of hopelessness’ – predicts the onset of heart disease and recovery from infarcts independently of other risk factors. (3)
Psychological distress is also a risk factor for stroke. (4) For people with a diagnosis of severe mental illness such as depression, the risk of physical illness is high: 46% of people with a mental health problem have a long-term physical health problem such as coronary heart disease or COPD. (5)
Mental illness also increases the risk of cancer, (6) musculoskeletal problems like back pain (7) and psychosomatic problems like irritable bowel (8) and possibly a range of other diseases. (9) Death rates are also higher in people with mental illness compared to people without mental illness, especially deaths from cardiovascular, respiratory and infectious diseases. (10)
Diagnosis of neurotic disorder (mental illness that falls short of psychosis) in general practice increases mortality over the next 11 years by 70% and a self-report of depression in population studies increases mortality by 50%. (11) People with psychotic disorders die on average 25 years earlier than the general population. (12)
Physical health problems are often associated with mental health problems
People with physical health problems, especially chronic diseases, are at increased risk of poor mental health, particularly depression and anxiety – around 30% of people with a long-term physical health condition also have a mental health problem. (13) In some cases, depression appears to result from specific biological effects of chronic illness.
Examples of this relationship include links between depression and central nervous system disorders such as Parkinson's disease, cerebrovascular disease, or multiple sclerosis, as well as endocrine disorders, such as hypothyroidism.
In other cases, the association between depression and chronic illness appears to be mediated by behavioural mechanisms, the limitations on activity imposed by the chronic illness leading to gradual withdrawal from rewarding activities. (14) Mental health problems can also increase the overall burden of illness in patients with chronic medical conditions, including the need for healthcare services.
For example, compared with those without depression, medical outpatients with depressive symptoms experienced decrements in quality of life (15) and had almost twice as many days of restricted activity or missed work because of illness. (16) Compliance with treatment for physical health conditions can also be an issue, with depression increasing the risk of non-compliance with treatment recommendations three fold. (17)
Mental health problems associated with physical illness can increase healthcare costs by more than 45% according to some international studies, which, if applied to NHS expenditure could mean that £8-13 billion of long-term physical health care costs are due to poor mental health. (18)
Treatments for mental illness such as anti-psychotic medications have been shown to increase the risk of physical ill-health. (19) More recent evidence has shown that despite the high risk of physical ill-health, people with mental health problems have less access to preventative and early interventions for physical illness including coronary angioplasty (20) (21) and may suffer discrimination in healthcare systems. (22)
Unhealthy lifestyles are often a response to stress
The unhealthy lifestyles and behaviours which plague the public’s health – smoking, excess alcohol consumption, misuse of illicit drugs, consumption of, sugary foods and over-eating in general – are used because they are effective in managing stress. For example, eating carbohydrates increases serotonin levels, which may boost mood (23). People find it very difficult to stop these behaviours because they can be addictive.
Other factors like social norms, availability, price and legality also play a role and provide important opportunities for regulation, but a key reason most people find it difficult to change their lifestyle is because the lifestyle assuages emotional distress.
- Almost 50% of all tobacco is now smoked by people with mental illness (24)
- Obesity is more prevalent among people with mental illness (25)
- Alcohol and drug misuse are commonly associated with mental illness (26)
- Mental health problems in childhood predict the adoption of unhealthy lifestyles in adolescence. (27)
Healthy foods, particularly it would seem fruit and vegetable consumption up to eight portions a day, (28) (29) can positively affect mental as well as physical health. Levels of physical activity can also impact on mental wellbeing in terms of mood, stress, self-esteem, anxiety, dementia and depression. (30) Current NICE guidance recommends the use of structured physical activity in the treatment of depression. (31)
Improving mental wellbeing can improve physical health
Emerging evidence suggests that improving mental wellbeing can contribute substantially to improving physical health, reducing morbidity and mortality. (32) (33) (34) (35) (36) For example, a meta-analysis found that positive mental well-being including positive affect (eg. positive mood, joy, happiness, vigor, energy) and positive trait-like dispositions (eg. life satisfaction, hopefulness, optimism, sense of humor) were significantly associated with reduced cardiovascular mortality in healthy populations, and with reduced death rates in patients with renal failure and with HIV (human immunodeficiency virus) infection. (37)
An association between positive affective traits and lower morbidity, decreased symptoms and pain has also been demonstrated. (38) Other studies have also shown that mental wellbeing can extend survival in cancer and renal disease. (39) (40)
Conversely, negative affective styles such as anxiety and hostility have been shown to predict increased risk for illness and mortality. (41) (42) Thus, public mental health interventions to promote mental wellbeing can work in conjunction with other public health interventions focused on behaviour change and risk factor reduction to improve physical health.
Social wellbeing – distinct from but interlinked with, and often incorporated into definitions of, mental wellbeing – can also affect physical health and is relevant here. A seminal study from 1979 found that relationships with others – partners, family and friends and to a lesser extent more formal social groups – reduced the risk of mortality. (43) More recent work reinforces the impact of the social context on health. (44) For example, a study in Wales showed that neighbourhood social capital is linked to the health of individuals within that neighbourhood. (45)
Evidence exists for interventions and approaches that promote mental wellbeing and improve physical health
At present services are provided to address mental health issues independently from services to address unhealthy lifestyles, and although lifestyle interventions are increasingly informed by psychological insights, they do not aim to promote mental health and wellbeing as an important part of the treatment package. Lifestyle change programmes could be more successful if they focused as much on mental health as they did on lifestyles and the interplay between the two. (46)
Good evidence exists for a range of public mental health interventions across the lifecourse that could be commissioned to promote mental wellbeing, encourage a healthy lifestyle and prevent chronic disease and mental illness. (47)
Starting and developing well
Robust evidence of effectiveness exists for public mental health interventions aimed to give children a good start in life. This is also an opportune time to intervene as 75% of mental illness starts before the age of 25 years (48) and many health risk behaviours such as smoking and substance misuse start in childhood, having a long-lasting adverse effect.
Living and working well
Interventions include a wide range of options to help people ‘live well’, promote mental health, and prevent the adoption of health risk behaviours, such as targeted approaches for smokers with mental disorder or physical activity programmes for those with depression.
Evidence-based interventions include physical activity to improve mental functioning, reduce mental illness, decrease social isolation and improve wellbeing in older people the elderly, (49) and addressing physical disabilities including hearing loss to improve quality of life and reduced social isolation. (50) (51)
Improving physical and mental health website jointly established by the Royal College of Psychiatrists and the Royal College of General Practitioners.
Physical Health Project by Rethink
3) Nabi H, Kivimaki M, De Vogli R, Marmot MG, Singh-Manoux A. Positive and negative affect and risk of coronary heart disease: Whitehall II prospective cohort study. BMJ 2008; 337:a118. (doi): p. 10.1136/bmj.a118.
7) Larson SL, Clark MR, Eaton WW. Depressive disorder as a long-term antecedent risk factor for incident back pain: a 13-year follow-up study from Baltimore Epidemiological Catchment Area Sample. Psychological Medicine. 2004; 34: 211-219.
8) Ruigomez A, Garcia Rodriguez LA, Panes J. Risk of irritable bowel syndrome after an episode of bacterial gastroenteritis in general practice: influence of comorbidities. Clinical Gastroenterology & Hepatology. 2007; 5: 465-469.
12) Parks J, Svendsen D, Singer P, Forty ME. Morbidity and mortality in people with serious mental illness. National Association of State Mental Health Programme Directors, Technical report No: 13, 2006.
16) Ormel J, Vonkorff M, Ustun TB, Pini S, Lorten A, Ordehinket T. Common mental disorders and disability across cultures. Results from the WHO Collaborative Study on Psychological Problems in General Health Care. JAMA 1994; 272(22): 1741-8.
21) Royal College of Psychiatrists.Whole-person care: from rhetoric to reality. Achieving parity between mental and physical health. Occasional paper OP88. 2013.
25) White M, Adamson A, Chadwick T, Howel D et al. The changing social patterning of obesity: An analysis to inform practice and policy development. Public Health Research Consortium. Report No: 4, 200
26) Crawford V. Co-Existing Problems of Mental Disorder and Substance Misuse (‘Dual Diagnosis’): A Review of Relevant Literature. Royal College of Psychiatrists’ Research and Training Unit. Final Report to the Department of Health, 2001
28) White BA, Horwath CC, Corners C. Many apples a day keep the blues away - daily experiences of negative and positive affect and food consumption in young adults. British J Healthy Psychology 2013. doi: 10.1111/bjhp.12021.
31) NICE. Depression: the treatment and management of depression in adults. Clinical guidelines.NICE CG90, 2009.
37) Chida Y, Steptoe A. Positive psychological well-being and mortality: a quantitative review of prospective observational studies. Psychosom Med. 2008; 70(7): 741-56. doi: 10.1097/PSY.0b013e31818105ba. Epub 2008 Aug 25.
41) Nabi H, Kivimaki M, De Vogli R, Marmot MG, Singh-Manoux A. Positive and negative affect and risk of coronary heart disease: Whitehall II prospective cohort study. BMJ 2008; 337:a118. (doi): p. 10.1136/bmj.a118.
47) Campion J, Fitch C. Guidance for commissioning public mental health services. Joint Commissioning Panel For Mental Health. 2012.
50) Chisolm T, Johnson CE, Danhauer JL, Portz LJ, Lesner S et al. A systematic review of health-related quality of life and hearing aids: final report of the American Academy of Audiology Task Force on the health-related quality of life benefits of amplification in adults. J Am Acad Audiol 2007;18(2): 151-83.