Lecture 1: Introduction & Global Burden of Mental Disease
Mental health: A state of well-being in which every individual realizes their own potential, can
cope with the normal stresses of life, can work productively and fruitfully, and is able to make a
contribution to their community.
Mental Health is disrupted for approximately 1/3 of individuals during their lifetime.
Despite the incidence, policy makers still fail to recognize the severity of the social,
economic, and human impact mental illness represents
Consequently, people with mental illness are often neglected and faced with stigma as
well as discrimination.
Mental disorders are a major drive of the growth of overall morbidity and disability globally – Five
types of mental illness are in the top 20 causes of global burden of disease:
1. Major depression
2. Anxiety disorders
3. Schizophrenia
4. Dysthymia
5. Bipolar disorder
Global Burden of Disease (GBD)
The Global Burden of Disease (GBD) is a comprehensive regional and global research program
aimed at assessing the impact of diseases, injuries, and risk factors on populations.
It provides a systematic framework to quantify the health loss due to various conditions and is
essential for guiding public health policies and resource allocation.
Nearly 1 billion people globally are affected by these conditions.
There are slightly more women than men affected overall:
Women higher in internalizing disorders Men higher in externalizing disorders
Importance of the global burden of disease (GBD):
1. Projecting Future Trends
The GBD provides valuable insights into the trajectory of diseases and health risks, enabling
predictions about future health challenges.
, By analyzing historical and current data, it helps in forecasting population health needs,
allowing for better preparedness against emerging health threats.
2. Guiding Policy Decisions and Setting Priorities
Policymakers rely on GBD data to craft informed health policies, ensuring that resources are
allocated to address the most pressing health issues.
It plays a crucial role in prioritizing health interventions, especially in resource-limited
settings, focusing on conditions with significant health impacts.
3. Expanding Beyond Traditional Health Measurements
GBD transcends standard health metrics like life expectancy by utilizing disability-adjusted
life years (DALYs), which capture both mortality and the impact of disabilities on quality of life.
This comprehensive approach allows for a better understanding of the social and economic
effects of diseases, addressing issues that may not be evident through traditional metrics.
Disability-Adjusted Life Years (DALYs):
DALYs are a measure used to quantify the overall burden of disease – One DALY represents the
loss of one year of "healthy" life due to either premature death or living with a disability.
Approximately two-thirds of DALYs are attributed to depressive disorders, anxiety disorders,
and drug/alcohol use disorders.
DALYs may underestimate the true burden of disease, as 93% of them are non-fatal. This
highlights the significant impact of non-fatal conditions on public health and individual
quality of life
While fatal conditions (those leading to death) are easier to quantify through YLL, non-
fatal conditions that affect quality of life but don’t necessarily cause death are
represented through YLD. However, 93% of the burden of disease attributed to DALYs is
non-fatal, meaning the majority of the disease burden comes from conditions that lead to
disability, not death.
Allows direct comparison of the burden across diseases.
YLL: The number of years lost due to premature death compared to a standard life expectancy.
YLD: The number of years spent living with a disability or illness, adjusted for the severity of the
condition.
Mental and Substance Use Disorders: Global Health Impact
In 2019, these disorders ranked 4th in terms of their overall impact on health as assessed by the
Global Burden of Disease [15.6% of global YLDs]. Notably, the prevalence of these disorders has
, been increasing since the 1990s.
True Share of Global DALYs (13%): Mental and substance use disorders contribute to 13% of
the total disease burden, which includes both years lost due to premature death (YLLs) and
years lived with disabilities (YLDs). This statistic emphasizes that while these conditions
significantly impact disability, they do not always lead to early death.
True Share of Global YLDs (32.4%): Over one-third (32.4%) of all years lived with disability
worldwide are attributed to mental and substance use disorders. This underscores the
substantial effect these conditions have on quality of life and highlights the urgent need for
targeted public health interventions.
Why the global burden of mental illness is underestimated:
1. Overlap between Psychiatric and Neurological Disorders:
Mental and neurological disorders overlap, but only conditions with a clear neuroanatomical
or neurophysiological basis are classified as neurological, leaving others under the psychiatric
category, potentially leading to underreporting of mental illness.
2. Suicide and Self-Harm Excluded from Mental Illness:
Instead, they are categorized separately under "injuries" in the Global Burden of Disease
(GBD) study, despite their strong link to mental disorders.
This coding practice leads to a lower reported burden for mental illness. In 2013, mental
illness accounted for 21.2% of YLDs but only 7.1% of DALYs due to this exclusion.
3. Chronic Pain Syndromes Conflated with Musculoskeletal Disorders:
Chronic pain syndromes are often grouped with musculoskeletal disorders, even when they
may be related to mental health conditions such as somatoform disorders.
Up to 30-80% of people with chronic pain also suffer from mental disorders like anxiety or
PTSD, but these connections are often overlooked in disease burden estimates.
4. Exclusion of Personality Disorders:
PD have a prevalence of 4-15%, and people with these disorders have shorter life expectancy
and higher comorbidity with other illnesses.
However, due to inconsistent data, they were excluded from the GBD 2013 estimates,
further underestimating the burden of mental illness.
5. Inadequate Consideration of Mortality from Co-Occurring Disorders:
People with severe mental illnesses have a 60% higher chance of premature death from non-
communicable diseases.
However, GBD calculations only attribute deaths directly caused by mental illness,
excluding deaths from associated physical health conditions.
This single-disease attribution underestimates the impact of mental disorders on overall
mortality.
Revising DALYs Estimates for Mental Illness is Required:
1. Include Neurological Symptoms in Mental Illness Category
Aggregate specific neurological symptoms within the mental illness category to reflect a more
accurate ranking in the GBD – This change could elevate mental illness from 5th to 3rd place
, in terms of burden.
2. Reallocate Self-Harm DALYs
Shift all DALYs related to self-harm from the "injuries" category to the mental health category
to better capture their connection to mental disorders.
3. Adjust Burden from Chronic Pain Syndromes
Reassign a portion of the burden from chronic pain syndromes to mental disorders rather
than just musculoskeletal disorders. It’s estimated that about one-third of the burden of
these pain syndromes is potentially attributable to mental health conditions.
Global Burden of Mental Disease
1. Increased Help-Seeking Behavior:
There has been a notable rise in the number of individuals seeking help for mental health
issues, indicating greater awareness and recognition of mental health needs.
2. Rising Mental Distress Among Young People:
Recent data shows a concerning increase in reported mental distress among young people
from 2005/2008 to 2017.
Age 12-17:
52% increase in Major Depression.
Age 18-25:
63% increase in Major Depression.
71% increase in serious psychological distress.
47% increase in suicide-related outcomes.
3. Contributing Factors:
The increases in mental health issues may be attributed to various cultural trends over the
last decade, alongside the significant impact of the Covid-19 pandemic, which has
exacerbated feelings of isolation, anxiety, and uncertainty among young people.
Criteria of Abnormality:
Personal distress Deviance from Statistical Impaired social
cultural norms infrequency functioning
Wakefield's harmful dysfunction theory posits that the concept of a medical disorder encompasses
two essential components:
1. Naturalistic Component (Dysfunction):
This component refers to the failure of a biological mechanism to perform its natural function
as designed by evolution. A disorder is identified when a specific mechanism fails to operate
in a way that would promote survival or well-being, indicating a biological dysfunction.
Example: A malfunction in the brain's regulatory mechanisms for mood could lead to
depression, which illustrates a failure of the biological system.
2. Value Component (Harm):
