Challenges to estimating the true global burden of mental disorders – Authors' reply

Abstract

We thank Harvey Whiteford and colleagues for their Correspondence and well considered comments, which make a valuable contribution to the debate on the burden of mental illness and to our Personal View in The Lancet Psychiatry.1Vigo D Thornicroft G Atun R Estimating the true global burden of mental illness.Lancet Psychiatry. 2016; 3: 171-178Summary Full Text Full Text PDF PubMed Scopus (1078) Google Scholar We share their views on the arbitrary division of neuropsychiatric disorders, the need to identify pain syndromes attributable to mental illness, the inclusion of personality disorders in the estimates of mental illness burden, and the need to quantify the contribution of mental illness to premature mortality. These are important research areas that need further development. Whiteford and colleagues rightly express important methodological caveats when estimating the burden of mental illness, such as the need to quantify effect sizes for risk of self-harm, to establish a case definition for somatoform disorders, and to develop better estimates for co-occurrence of personality and other mental disorders. We concur with these important research priorities and the need to address methodological and data challenges to provide more precise estimates of the burden of mental illness than exist at present, which are needed to inform the development of a health system's response commensurate with the burden. Notwithstanding methodological challenges, 0% attribution of chronic pain syndromes to mental illness underestimates the mental illness burden, as does the attribution of 100% self-harm burden to the category of injuries.2Whiteford HA Degenhardt L Rehm J et al.Global burden of disease attributable to mental and substance use disorders: findings from the Global Burden of Disease Study 2010.Lancet. 2013; 382: 1575-1586Summary Full Text Full Text PDF PubMed Scopus (3820) Google Scholar Ferrari and colleagues3Ferrari A Norman R Freedman G Baxter A Pirkis J The burden attributable to mental and substance use disorders as risk factors forn suicide: findings from the Global Burden of Disease Study 2010.PLoS One. 2014; 9: e91936Crossref PubMed Scopus (266) Google Scholar proposed a partial correction, reattributing 0·9% of global disability-adjusted life-years (DALYs) to mental illness, but erred on the side of caution by imposing a ceiling of 68·3% to suicides attributable to mental illness in China and India. Phillips and colleagues' research4Phillips MR Shen Q Liu X et al.Assessing depressive symptoms in persons who die of suicide in mainland China.J Affect Disord. 2007; 98: 73-82Summary Full Text Full Text PDF PubMed Scopus (71) Google Scholar allows for a very different conclusion: it is the exclusion of subsyndromic depressive states and personality disorders that leads to underestimation of the causal link of mental illness and suicide. Indeed, in later work Phillips and colleagues4Phillips MR Shen Q Liu X et al.Assessing depressive symptoms in persons who die of suicide in mainland China.J Affect Disord. 2007; 98: 73-82Summary Full Text Full Text PDF PubMed Scopus (71) Google Scholar report that underlying depression prevalence doubles when using culturally appropriate probes. Exclusion of more than a third of self-harm DALYs from mental disorders leads to unjustified underestimation of the burden of mental illness in view of the under-reporting in many countries, including in China and India, due to stigma, which compounds the exclusion of personality disorders and sub-syndromic states. There is clearly a trade-off between upholding Global Burden of Disease assumptions and providing a more realistic estimate of mental illness burden—while noting data limitations and uncertainties—to inform policy for a specialty that for too long has been starved of attention and funding worldwide. We declare no competing interests. RA and DV conceived and wrote the first draft. GT added to the draft. All authors contributed to the final version. Estimating the true global burden of mental illnessWe argue that the global burden of mental illness is underestimated and examine the reasons for under-estimation to identify five main causes: overlap between psychiatric and neurological disorders; the grouping of suicide and self-harm as a separate category; conflation of all chronic pain syndromes with musculoskeletal disorders; exclusion of personality disorders from disease burden calculations; and inadequate consideration of the contribution of severe mental illness to mortality from associated causes. Full-Text PDF Challenges to estimating the true global burden of mental disordersVigo and colleagues1 in The Lancet Psychiatry identify five reasons why the burden of mental disorders might be underestimated in the Global Burden of Disease (GBD) studies. The issues raised are important and, as members of the team that assembles the mental and substance use disorder GBD estimates, we would make the following comments. Full-Text PDF