People with bipolar disorder or schizophrenia (often referred to as severe mental illness, or SMI) die on average 10-20 years sooner than the general population. This difference in life expectancy is commonly known as the ‘mortality gap’. It has been a consistent research finding for years (Hayes, Miles, Walters, King, & Osborn, 2015). This study by Joseph Hayes et al, published in the British Journal of Psychiatry, compares changing death rates in population groups from 2000 to 2014. It is accompanied by an editorial on the same topic by Siddiqi et al. Other Elves have also written blogs on this subject (Elena Marcus, 2015).

Psychiatrists and other mental health professionals often worry about our patients dying by suicide. Whilst people with severe mental illness are at greater risk of suicide, cardiovascular disease accounts for much of the gap in life expectancy. The reasons for the greater health burden are several, complex, and intertwining: direct harms from psychotropic medication, socioeconomic disadvantage, stigma and a lack of focus on physical health, and, for some, reduced self-advocacy and engagement with professional services. In their editorial, Siddiqi and colleagues point out that there is no shortage of reports, policies and initiatives addressing these factors to reduce the mortality gap, which leads to the obvious question: what impact, if any, have these had?

Methods

• The investigators used information from a database of primary care electronic health records from 2000 to 2014. It included over 11 million people, encompassing both those with an SMI and those without
• They looked at overall mortality, cardiovascular problems and cardiovascular deaths, suicide and self-harm rates
• They compared groups of people with bipolar disorder and schizophrenia with the wider population
• The investigators used a technique called Cox proportional hazards regression to compare mortality between groups.

Results

Consistent with previous studies, the investigators found that mortality was higher in those with bipolar disorder and schizophrenia relative to the general population. The result held after adjustment for possible confounding factors.

The crucial question is whether things are getting better with time. Overall mortality rates in both bipolar disorder and schizophrenia fell between 2000 and 2014. On the face of it, that is good news. However, the authors compared the mortality rate for people with bipolar and schizophrenia to a matched group of people from the general population. The difference between the two groups had actually widened.

Hayes et al suggested various factors which might have adversely influenced mortality rates among those with serious mental illness:

• National health campaigns, such as smoking cessation interventions, have been less effective for people with bipolar disorder and schizophrenia
• Medications may reduce overall mortality, but higher doses and polypharmacy may increase it
• Deinstitutionalisation may have been successful in terms of integrating people back into society, but it has been suggested that people with serious mental illness living in the community might require greater care and advocacy in such ‘less restrictive’ but also less supported settings
• It is possible that the 2008 economic recession and subsequent changes in governmental social and healthcare policy may have had a greater impact on people with schizophrenia and bipolar disorder.

Conclusions

The authors of this study conclude that:

although there have been important reductions in overall mortality since 2000, interventions to improve health outcomes for those with bipolar disorder or schizophrenia have not reduced the mortality gap.

Strengths and limitations

This is a very well powered study with an enormous sample size. It included almost 6% of the UK population, and followed them for over a decade. We can thus confidently generalise the findings for people living with bipolar disorder and schizophrenia across the UK. Application to other jurisdictions, even those with similar models of mental health care, requires caution: as well as clinical considerations, specific social and healthcare policy initiatives will be important confounders, and ones that may vary considerably between countries.

The authors point out a number of other limitations with their study. It would have been useful to cross-check the data with information from death certificates, but this wasn’t possible. Nor were they able to assess the effect of duration of illness on life expectancy.

Databases are only as good as the information entered into them. This database was from primary care; however, its mental health information has previously been well-validated (Hardoon et al., 2013; Nazareth, King, Haines, Rangel, & Myers, 1993).

This study gives us an up-to-date assessment of the mortality gap, but, more importantly, how this has changed over time. It heads off complacency by demonstrating that the situation is not improving relative to the general population despite major, and multi-level, efforts and strategies. However, it is not able to advance our knowledge of why the mortality gap is widening: life expectancy has improved in the SMI cohort, so something is working, but it’s not working as well as in the general population. The authors are only able to speculate about the mechanisms that cause a severe mental illness to reduce life expectancy, and which intervention(s) are most and least effective at ameliorating this, including those aimed at the whole population, and those targeted at specific groups.

Implications for practice

This paper reminded us of the moving article by journalist and former government advisor Alastair Campbell. He told the story of his brother Donald, who developed schizophrenia in his early 20s whilst serving in the Scots Guards. He took antipsychotics for years and had periods in hospital. Despite his illness, he worked for 27 years as a security guard at Glasgow University. He was also a talented musician: he played the bagpipes. Donald taught and composed music, and was the principle piper at Glasgow University ceremonies. Alastair described the physical effects that years of mental illness and treatment had had on Donald. He suffered from obesity and lung problems. Donald was only 62 when he died, more than 20 years younger than his mother and father. This is the human story of the mortality gap: the years of poor health at the end of Donald’s life; the years of retirement he missed.

So what should we do? This study clearly demonstrates that further research is required. We need a comprehensive picture of the factors that reduce life expectancy in people with severe mental illness and, critically, the effectiveness of general and targeted interventions in improving this. This is likely to involve a constellation of adverse factors including physical and mental ill-health, lifestyle choices and social disadvantage. The wider strategy must span specialist, primary care and public health settings. Studies like this have an important role to play in measuring our progress in narrowing the mortality gap.

Conflicts of interest

Judith Harrison works with Joseph Hayes on other projects. Both Judith Harrison and Derek Tracy are on the editorial board of the BJPsych, as is Joseph Hayes. We have no other interests to declare.

Links

Primary paper

Hayes JF, Marston L, Walters K, King MB, Osborn DPJ. (2017) Mortality gap for people with bipolar disorder and schizophrenia: UK-based cohort study 2000–2014. The British Journal of Psychiatry Jul 2017, bjp.bp.117.202606; DOI: 10.1192/bjp.bp.117.202606

Other references

Campbell, A. My Brother Donald: Please Spread His Story Far And Wide, And Join The Fight For Better Mental Health HuffPost 16 August 2016

Hardoon, S., Hayes, J. F., Blackburn, R., Petersen, I., Walters, K., Nazareth, I., & Osborn, D. P. J. (2013). Recording of severe mental illness in United Kingdom primary care, 2000-2010.  PloS One, 8(12), e82365. doi:10.1371/journal.pone.0082365

Hayes, J. F., Miles, J., Walters, K., King, M., & Osborn, D. P. J. (2015). A systematic review and meta-analysis of premature mortality in bipolar affective disorder. Acta Psychiatrica Scandinavica, 131(6), 417–425. doi:10.1111/acps.12408 [PubMed Abstract]

Nazareth, I., King, M., Haines, A., Rangel, L., & Myers, S. (1993). Accuracy of diagnosis of psychosis on general practice computer system. BMJ (Clinical Research Ed.), 307(6895), 32–4. http://www.ncbi.nlm.nih.gov/pubmed/8343670

Siddiqi N., Doran, T., Prady, S.L., Taylor, J. (2017) Closing the mortality gap for severe mental illness: are we going in the right direction? BJPsych, 211, 1-2. doi:10.1192/bjp.bp.117.203026

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