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Chapter 2: Burden of Mental and Behavioural Disorders: Previous page | 1,2,3,4,5,6,7,8

Impact of disorders

  Chapter 2

Mental and behavioural disorders have a large impact on individuals, families and communities. Individuals suffer the distressing symptoms of disorders. They also suffer because they are unable to participate in work and leisure activities, often as a result of discrimination. They worry about not being able to shoulder their responsibilities towards family and friends, and are fearful of being a burden for others.

It is estimated that one in four families has at least one member currently suffering from a mental or behavioural disorder. These families are required not only to provide physical and emotional support, but also to bear the negative impact of stigma and discrimination present in all parts of the world. While the burden of caring for a family member with a mental or behavioural disorder has not been adequately studied, the available evidence suggests that it is indeed substantial (Pai & Kapur 1982; Fadden et al. 1987; Winefield & Harvey 1994). The burden on families ranges from economic difficulties to emotional reactions to the illness, the stress of coping with disturbed behaviour, the disruption of household routine and the restriction of social activities (WHO 1997a). Expenses for the treatment of mental illness often are borne by the family either because insurance is unavailable or because mental disorders are not covered by insurance.

Figure 2.1 Burden of neuropsychiatric conditions as a proportion

In addition to the direct burden, lost opportunities have to be taken into account. Families in which one member is suffering from a mental disorder make a number of adjustments and compromises that prevent other members of the family from achieving their full potential in work, social relationships and leisure (Gallagher & Mechanic 1996). These are the human aspects of the burden of mental disorders, which are difficult to assess and quantify; they are nevertheless important. Families often have to set aside a major part of their time to look after the mentally ill relative, and suffer economic and social deprivation because he or she is not fully productive. There is also the constant fear that recurrence of illness may cause sudden and unexpected disruption of the lives of family members.

The impact of mental disorders on communities is large and manifold. There is the cost of providing care, the loss of productivity, and some legal problems (including violence) associated with some mental disorders, though violence is caused much more often by "normal" people than by individuals with mental disorders.

One specific variety of burdens is the health burden. This has traditionally been measured ­ in national and international health statistics ­ only in terms of incidence/prevalence and mortality. While these indices are well suited to acute diseases that either cause death or result in full recovery, their use for chronic and disabling diseases poses serious limitations. This is particularly true for mental and behavioural disorders, which more often cause disability than premature death. One way to account for the chronicity of disorders and the disability caused by them is the Global Burden of Disease (GBD) methodology. The methodology of GBD 2000 is described briefly in Box 2.2. In the original estimates developed for 1990, mental and neurological disorders accounted for 10.5% of the total DALYs lost due to all diseases and injuries. This figure demonstrated for the first time the high burden due to these disorders. The estimate for 2000 is 12.3% for DALYs (see Figure 2.1). Three neuropsychiatric conditions rank in the top twenty leading causes of DALYs for all ages, and six in the age group 15-44 (see Figure 2.2). In the calculation of DALYs, recent estimates from Australia based on detailed methods and different data sources have confirmed mental disorders as the leading cause of disability burden (Vos & Mathers 2000). From an analysis of trends, it is evident that this burden will increase rapidly in the future. Projections indicate that it will increase to 15% in the year 2020 (Murray & Lopez 1996a). The proportion of DALYs and YLDs for neuropsychiatric conditions globally and regionally are given in Figure 2.1.

Box 2.2 Global Burden of Disease 2000

In 1993 the Harvard School of Public Health in collaboration with the World Bank and WHO assessed the Global Burden of Disease (GBD).1 Aside from generating the most comprehensive and consistent set of estimates of mortality and morbidity by age, sex and region ever produced, GBD also introduced a new metric­disability-adjusted life year (DALY)­to quantify the burden of disease.2, 3. The DALY is a health gap measure, which combines information on the impact of premature death and of disability and other non-fatal health outcomes. One DALY can be thought of as one lost year of 'healthy' life, and the burden of disease as a measurement of the gap between current health status and an ideal situation where everyone lives into old age free of disease and disability. For a review of the development of DALYs and recent advances in the measurement of burden of disease see Murray & Lopez (2000).4

The World Health Organization has undertaken a new assessment of the Global Burden of Disease for the year 2000, GBD 2000, with the following specific objectives:

DALYs for a disease are the sum of the years of life lost due to premature mortality (YLL) in the population and the years lost due to disability (YLD) for incident cases of the health condition. The DALY is a health gap measure that extends the concept of potential years of life lost due to premature death (PYLL) to include equivalent years of 'healthy' life lost in states of less than full health, broadly termed disability.

GBD 2000 results for neuropsychiatric disorders given in this report are based on an extensive analysis of mortality data for all regions of the world, together with systematic reviews of epidemiological studies and population-based mental health surveys. Final results of GBD 2000 will be published in 2002.

1 World Bank (1993). World development report 1993: investing in health. New York, Oxford University Press for the World Bank.

2 Murray CJL, Lopez AD, eds (1996a). The global burden of disease: a comprehensive assessment of mortality and disability from diseases, injuries and risk factors in 1990 and projected to 2020. Cambridge, MA, Havard School of Public Health on behalf of the World Health Organization and the World Bank (Global Burden of Disease and Injury Series, Vol. I).

3 Murray CJL, Lopez AD (1996b). Global health statistics. Cambridge, MA, Harvard School of Public Health on behalf of the World Health Organization and the World Bank (Global Burden of Disease and Injury Series, Vol. II).

4 Murray CJL, Lopez AD (2000). Progress and directions in refining the global burden of disease approach: a response to Williams. Health Economics, 9: 69-82.

Taking the disability component of burden alone, GBD 2000 estimates show that mental and neurological conditions account for 30.8% of all years lived with disability (YLDs). Indeed, depression causes the largest amount of disability, accounting for almost 12% of all disability. Six neuropsychiatric conditions figured in the top twenty causes of disability (YLDs) in the world, these being unipolar depressive disorders, alcohol use disorders, schizophrenia, bipolar affective disorder, Alzheimer's and other dementias, and migraine. (see Figure 2.3).

Figure 2.2 Leading causes of disability-adjusted life years (DALYs), in all ages and in 15–44-year-olds, by sex, estimates for 2000a

The disability caused by mental and neurological disorders is high in all regions of the world. As a proportion of the total, however, it is comparatively less in the developing countries, mainly because of the large burden of communicable, maternal, perinatal and nutritional conditions in those regions. Even so, neuropsychiatric disorders cause 17.6% of all YLDs in Africa.

Figure 2.3 Leading causes of years of life lived with disability (YLDs), in all ages and in 15–44-year-olds, by sex, estimates for 2000a

There are varying degrees of uncertainty in GBD 2000 estimates of DALYs and YLDs for mental and neurological disorders, reflecting uncertainty in the prevalence of the various conditions in different regions of the world, and uncertainty in the variation of their severity distributions. In particular, there is considerable uncertainty in the estimates of prevalence of mental disorders in many regions, reflecting the limitations of self-report instruments for classifying mental health symptoms in a comparable way across populations, limitations in the generalizability of surveys in subpopulations to broader population groups, and limitations in the information available to classify the severity of disabling symptoms of mental health conditions.

Economic costs to society

The economic impact of mental disorders is wide ranging, long lasting and huge. These disorders impose a range of costs on individuals, families and communities as a whole. Part of this economic burden is obvious and measurable, while part is almost impossible to measure. Among the measurable components of the economic burden are health and social service needs, lost employment and reduced productivity, impact on families and caregivers, levels of crime and public safety, and the negative impact of premature mortality.

Some studies, mainly from industrialized countries, have estimated the aggregate economic costs of mental disorders. One such study (Rice et al. 1990) concluded that the aggregate yearly cost for the United States accounted for about 2.5% of gross national product. A few studies from Europe have estimated expenditure on mental disorders as a proportion of all health service costs: in the Netherlands, this was 23.2% (Meerding et al. 1998) and in the United Kingdom, for inpatient expenditure only, it was 22% (Patel & Knapp 1998). Though scientific estimates are not available for other regions of the world, it is likely that the costs of mental disorders as a proportion of the overall economy are high there too. Although estimates of direct costs may be low in countries where there is low availability and coverage of mental health care, these estimates are spurious. Indirect costs arising from productivity loss account for a larger proportion of overall costs than direct costs. Furthermore, low treatment costs (because of lack of treatment) may actually increase the indirect costs by increasing the duration of untreated disorders and associated disability (Chisholm et al. 2000).

All these estimates of economic evaluations are most certainly underestimates, since lost opportunity costs to individuals and families are not taken into account.

Impact on the quality of life

Mental and behavioural disorders cause massive disruption in the lives of those who are affected and their families. Though the whole range of unhappiness and suffering is not measurable, one of the methods to assess its impact is by using quality of life (QOL) instruments (Lehman et al. 1998). QOL measures use the subjective ratings of the individual in a variety of areas to assess the impact of symptoms and disorders on life (Orley et al. 1998). A number of studies have reported on the quality of life of individuals with mental disorders, concluding that the negative impact is not only substantial but sustained (UK700 Group 1999). It has been shown that quality of life continues to be poor even after recovery from mental disorders as a result of social factors that include continued stigma and discrimination. Results from QOL studies also suggest that individuals with severe mental disorders living in long-term mental hospitals have a poorer quality of life than those living in the community. A recent study clearly demonstrated that unmet basic social and functioning needs were the largest predictors of poor quality of life among individuals with severe mental disorders (UK700 Group 1999).

The impact on quality of life is not limited to severe mental disorders. Anxiety and panic disorders also have a major effect, in particular with regard to psychological functioning (Mendlowicz & Stein 2000; Orley & Kuyken 1994).

Chapter 2: Burden of Mental and Behavioural Disorders: 1,2,3,4,5,6,7,8 | Next page

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