The epidemiology and burdens of mental disorder

Question 1

‘Why counting stuff is useful’, or what is epidemiology?

Answer 1

According to the Oxford English Dictionary, is ‘the branch of medicine that deals with the incidence and transmission of disease in populations especially with the aim of controlling it’.

Question 2

What does epidemiology involves?

Answer 2

1. Defining ‘disorders’;
2. Counting and mapping disorders in a specific place and time;
3. Linking the occurrence of disorder to causative factors;
4. Identifying appropriate (public health) interventions.

Question 3

What does epidemiology do?

Answer 3

Epidemiology studies, in a scientific, systematic, data-drive way the distribution or frequency, patterns or determinants, causes or risk factors of health related events in specific populations and works directly with public health to study the control of such health problems.

Question 4

What are the two broad strands of epidemiology?

Answer 4

1. Descriptive
2. Analytical (focuses on causes)

Question 5

What is the main are of focus of analytic epidemiology?

Answer 5

a. Prevalence (the proportion of a particular population found to be affected by a medical condition at a specific time).

b. Incidence (a measure of the number of new cases of a characteristic that develop in a population in a specified time period)

c. Variations between populations

d. Comorbidities (a disease or medical condition that is simultaneously present).

e. Burden of disorder (the impact of a health problem as measured by financial cost, mortality, morbidity, or other indicators).

Question 6

Who was one of the first to do ‘epidemiological thinking’?

Answer 6

John Snow and the Broad Street pump in 1954.
There was an outbreak of cholera so Snow mapped the incidence of cholera, and mapped it to water pump areas.

Question 7

Explain the example of epidemiology, tobacco and lung cancer.

Answer 7

A study by Doll & Hill looked at the death rates from lung cancer amongst doctors (1951-1961).

Then related the death rates to the average number of cigarettes smoked per day by those doctors.

They found a straight relations between both variables which proved a very strong argument that smoking caused lung cancer.

This data led to a medical revolution.

Question 8

Psychiatric epidemiology is a branch of epidemiology. Explain.

Answer 8

Psychiatric epidemiology looks at the distribution of mental health disorders in population.

Helps understand the onset, cause and outcomes of mental disorders.

Helps measure the burden of mental disorders on society.

Seeks to identify casual mechanisms underlying the development of mental disorders.

Aims to prevent and modify outcomes for the best.

Question 9

What are three basic concepts in psychiatry epidemiology?

Answer 9

1. Caseness

defining the presence of a mental disorder using specific operational criteria. (whether or not a subject has the condition of interest).

2. Incidence

the transition TO caseness over a period of time (the proportion of an initially disease-free population that develops disease, becomes injured, or dies during a specified period of time).

3. Prevalence

the proportion of people who are cases at any particular time or over a defined period e.g, lifetime prevalence.

Question 10

Explain the descriptive perspective of epidemiology.

Answer 10

If we look though the lenses of descriptive epidemiology it possible to:

a. identify the population of interest.
b. sample the population
c. use structured views (interviews), which provides data on symptoms and disability
d. provide estimates of caseness, diagnosis, and the burden of disease.

Descriptive epidemiology describes the outbreak in terms of person, place and time. “Person” refers to socio-demographic characteristics of cases and includes variables such as age, ethnicity, sex/gender, occupation, and socioeconomic status.

Diagnostic criteria used is the DSM. However, this criteria is reliable but has contested validity.

Question 11

Explain the analytical perspective of epidemiology.

Answer 11

If we look though the lenses of analytical epidemiology it possible to:

a. same steps as descriptive epidemiology
b. break down population in structured way
c. identify causes or other variables to be measured
(e.g., population-based surveys, case control studies, comparison of non-cases with cases)
d. apply methodology.

Analytic epidemiology is concerned with the search for causes and effects, or the why and the how. Epidemiologists use analytic epidemiology to quantify the association between exposures and outcomes and to test hypotheses about causal relationships.

Question 12

What are some significant limitations to US epidemiological studies?

Answer 12

1. They do not tell us anything useful about low -prevalence disorders such as schizophrenia.
2. Missed out mental disorders in the elderly.

Question 13

What are the National Comorbidity Study Replication (NCSR) headline findings about mental disorders?

Answer 13

1. They are common. (26 % prevalence in a year and 46% lifetime)
2. They are of early onset (begun by the age of 24)
3. The majority are serious or moderate
4. Comorbidity is common (more than one disorder at a time)
5. Access to treatment is very limited or poor quality and delayed.

Question 14

What does epidemiology data from Wittchen and Jacobi tell us about mental disorders?

Answer 14

1. Mental disorders are associated with a disability burden (in terms of work days lost)
2. Generally, there is low treatment rates (only 26% of cases had any consultation with a professional)
3. There is a considerable degree of unmet needs.

Question 15

Explain the Wittchen and Jacobi paper from 2005.

Answer 15

Meta-analytic techniques, and re-analysis
27 elegible studies
150,000 subjects
16 european contries

results:

prevalence of mental disorders is 27% in a 12 month period (similar to the NCSR data)

comorbidity, 1/3 of people had more than one disorder

little evidence exist for cultural or country variation

most frequent disorders: anxiety disorders, depressive, somatoform & substance dependence.

Question 16

What is the consistency between US and UK data on mental disorders?

Answer 16

Over a quarter of the adult population (18 to 65) will meet diagnostic criteria in a year

Only a small portion are receiving treatment

Question 17

Name the tools used by analytic epidemiology when looking towards causation.

Answer 17

1. Relative risk or risk ratio

The ratio of the probability of an event occurring in an exposed group to the same probability in a comparison group.

Question 18

What do we know about psychosis risk ratio?

Answer 18

Paul Bebbington et al. found relative risk ratio of 10.1 in child sexual abuse and psychosis.

History of psychosis in a first degree relative, risk ratio is 9.3

Children of emigrants to the UK, risk ratio is 7.0

Question 19

What are the causal mechanisms for psychosis according to epidemiology?

Answer 19

Historically, interest has been on social factors:

emigration
urbanicity
psychosocial stress
life events

More recently, interest is more on mechanism through which social forces results in the onset of mental disorders. This might be called new psychiatric epidemiology.

Question 20

What are the new potential causal mechanisms for psychosis, according to new psychiatric epidemiology?

Answer 20

1. Inflammatory biomarkers
2. Gene-environment interactions
3. The impact of social environment of neurobiology
4. Potential genome-wide research
5. Epigenetics

Question 21

What is the paradigmatic disorder for the burden of mental illness?

Answer 21

Schizhophrenia

Symptoms such as hallucinations, delusions, affective and anxiety symptoms, etc.

It also causes functional impairments, inability to carry out day-to-day tasks.

It causes cognitive impairment such as memory loss, language and executive function.

People end up in the hospital, treated with medication and have side effects, they loss self-identity, suffer discrimination, self-stigmatisation.

Then they experience unemployment, social isolation, small likelihood of marriage, premature mortality.

Question 22

What is the burden of mental disorder for carers?

Answer 22

Emotional

Practical

Social (stigma as well)

Financial

Question 23

From a phenomenological approach, explain the impact of mental disorder.

Answer 23

Larry Davison’s book: Living outside Mental Illness describes in detail the processes of becoming ill and escaping that identity.

The book is based on phenomenological enquiry, meaning people talk about their personal experiences.

Uses the metaphor of falling into a black hole, however, there is a way out.

Question 24

Why is ‘first person literature’ important?

Answer 24

It is an important part of the contemporary recovery narrative in mental health.

Question 25

What is WHO definition of disability?

Answer 25

According to WHO, disability is an umbrella term covering impairments, activity limitations, and participation restrictions.

An impairment is a body-functional structure.

Question 26

What can we say about disability?

Answer 26

WHOs definition is essentially design for people with body dysfunctions.

Question 27

How can we measure the impact of mental disorders?

Answer 27

1. Quality of life (QOL)
2. Health related quality of life
3. QALYs (Quality-adjusted Life Years)
4. DALYs (Disability-adjusted life Years)

Question 28

Explain the concept of quality of life?

Answer 28

According to the Centres for Disease Control (CDC), QOL is a multidimensional concept that includes subjective evaluations of both negative and positive aspects of life.

Question 29

What are the domains of QOL?

Answer 29

Health is one of the most important domains of QOL.

jobs,
housing,
schools,
neighbourhood,
culture,
values,
spirituality,

Question 30

Name the six broad approaches to QOL.

Answer 30

By looking at these approaches you can measure QOL in people with mental disorders.

1. Objective indicators

(income, living conditions, access to resources, participation in occupational and social roles.

2. Needs satisfaction

(Maslow’s hierarchy of needs: from the most basic to self-actualisation.

3. Subjective well being

(current hedonic state, actual happiness, overall satisfaction with life or some particular domains of life).

4. Psychological well-being

(moral, self-esteem, self efficacy, sense of autonomy and control).

5. Capabilities

(developed by Amartya Sen, focuses on what people are able to do in order to achieve outcomes that they value.

Poverty, ignorance and oppression represent a capability deprivation.

6. Health-related quality of life (also used to measure the burden)

Question 31

What is Health-related QOL?

Answer 31

Various definitions:

1. A person’s subjective perception of the impact of health status: well-being, physical, psychological, social functioning..
2. A combination of a person’s physical, mental and social well-being.
3. An individual’s or a group’s perceived physical and mental health over time.

Question 32

Name two important measures for HRQOL?

Answer 32

SF-36 and EQ-5D health questionnaires.

Question 33

What is a QALY?

Answer 33

Quality adjusted life years

A generic measure of disease burden, including both the quality and the quantity of life lived.

Measures how valuable are health interventions over the years gained. How cost effective can be an intervention in years gained, meaning, is it worth doing x or Y for 1 year gained?

= survival years x utility associated to a health state. Full health is 1, death is 0.

Question 34

What is a DALY?

Answer 34

Disability adjusted life years

The disability-adjusted life year is a measure of overall disease burden, expressed as the number of years lost due to ill-health, disability or early death

Years lived with disability plus years of lost life = DALYs

Years lived with disability = prevalence of disorder x disability weight (full disability 1, perfect health 0)

Question 35

What does GBD stands for?

Answer 35

Global Burden of Disease by WHO

Question 36

What are WHO’s GBD headlines?

Answer 36

1. Mental disorders are a leading cause os disability across the world, not usually fatal, so people live with a long-term disability.
2. The most disabling mental disorder is depression. It is common and disabling.
3. Schizophrenia and bipolar disorder are important and have a greater impact on health budgets.
4. Dementia will become an ever larger source of disability.
5. Burden of disease varies across countries, particularly in relation to the age structure of the population.
6. WHO uses DALYs as and index of disability.

Question 37

From 2005 to 2011 Wittchen and Jacobi updated the report. What happened?

Answer 37

They widened the age range and the scope of disorders and prevalence went up to 38,2 % over a 12 month period.

Measured in DALYs, female neuropsychiatric disorders affects 30.1% of Europe and Switzerland population whereas males are affected by 23.4%

1.Unipolar depression (higher in females)
2. Dementias (higher in females)
3. Schizophrenia (higher in males)
4. Bipolar disorder (higher in males)

The new (revisited) estimates confirm that:

1. Disorders of the brain are the major contributor to the total EU disease burden.
2. Depression and ‘less serious’ disorders are associated with a substantial degree of disability.
3. Depression is now the most important single contributor to the total disease burden.
4. There is a substantially different disability differences between males and females.

Question 38

Which factors should be considered for the economic impact of mental disorder?

Answer 38

1. Treatment and care costs
2. Social security costs
3. Costs due to lost of productivity
4. Cost experience by carers
5. Hidden costs such as suffering and pain.

Question 39

What were the World Economic Forum results on the Global Economic Burden of Non-Communicable Diseases report of 2011?

Answer 39

Estimates global cost of mental illness at nearly 2.5 trillions US dollars, were 2 thirds are indirect costs, with a projected increase to over 6 trillions by 2030.

Putting it in perspective:

The entire global health spending in 2009 was 5.1 trillion.

Question 40

How do we measure prevalence?

Answer 40

1. Estimate the prevalence of disorder.
2. Weight disorder by disability or gradings for severity.
3. Take into account the impact of premature mortality.

There are a number os studies estimating burden of disorders by using different methodologies.

Question 41

How are DALYs measured?

Answer 41

DALYs = YLD (years lived with disability) + YLL (years of lost life)

YLD = (prevalence x weighting of disorder on the person or group)

YLL = impact of premature mortality

weighting= perfect health is 0 and extreme illness is 1.

Question 42

Resume the summary statistics from global mental health studies on neuropsychiatric disorders by Harvey Whiteford.

Answer 42

In absolute numbers, neuropsychiatric disorders have 199 million DALYs.

Being unipolar depressive disorder on top with 65 DALYs or 32% worldwide.

In high income countries 10 DALYs for Unipolar depression disorder and 55,5 for low-income countries.

Next in importance is alcohol use disorders with 24 DALYs or 11.9 %.

In HIC is 4.2 DALYS and in LIC is 19.5.

Schizophrenia and bipolar follow in DALYs worldwide.

Alzheimer and dementia 4.4 %, however, as the population grows older they will become more significant.

Question 43

Why is Global Burden of Disease (GBD) important?

Answer 43

1. Helps policy makers understand the impact fo mental disorder at a population level.
2. Show that mental disorders constitute the most important category of non-communicable disease (NCD) in terms of burden of disease.
3. Provides an argument for investment in mental health research and mental health services.

Question 44

What can be done about the societal burden of mental disorders?

Answer 44

There needs to be a:

1. Research agenda
2. Policy Agenda
3. Practice agenda

Question 45

What is the Grand Challenge in Global Mental Health?

Answer 45

Launched in 2010

Is a consortium of mental health researchers, advocates and clinicians.

In 2011 they announced a series of research priorities for improving the lives of people with mental illness around the world.

The top five challenges ranked by disease-burden reduction, impact on equity, immediacy of impact, and feasibility should serve as a starting point for immediate research and prioritisation of policies.

Other goals:

1. Identify root causes, risk and protective factors.
2. Advance prevention and implementation of early interventions.
3. Improve treatments and expand access to care.
4. Raise awareness of the global burden.
5. Build human resource capacity.
6. Transform health system and policy responses.

Question 46

What is the way forwards according to Dr. Halloway?

Answer 46

1. Relatively simple interventions can have a big impact (e.g., Access to Psychological Therapies (IAPT) promises therapy for all.)
2. Some sever mental health disorders do not respond well to simple interventions and should be treated by specialists.
3. There is rather little evidence that policy emphasis towards prevention and early interventions works.
4. Further research into potentially modifiable factors or risk factor is needed. (e.g., child sexual abuse, poverty, unemployment).