The epidemiology of depression has been studied across the world.
Depression is a major cause of
morbidity
A disease is a particular abnormal condition that adversely affects the structure or function of all or part of an organism and is not immediately due to any external injury. Diseases are often known to be medical conditions that are asso ...
and
mortality worldwide, as the
epidemiology
Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and Risk factor (epidemiology), determinants of health and disease conditions in a defined population, and application of this knowledge to prevent dise ...
has shown. Lifetime prevalence estimates vary widely, from 3% in Japan to 17% in India. Epidemiological data shows higher rates of depression in the
Middle East
The Middle East (term originally coined in English language) is a geopolitical region encompassing the Arabian Peninsula, the Levant, Turkey, Egypt, Iran, and Iraq.
The term came into widespread usage by the United Kingdom and western Eur ...
, North Africa, South Asia and the
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
than in other regions and countries. For most countries among the 10 studied, the number of people who experience depression during their lifetimes falls within an 8–12% range.
In North America, the probability of having a
major depressive episode
A major depressive episode (MDE) is a period characterized by symptoms of major depressive disorder. Those affected primarily exhibit a depressive mood for at least two weeks or more, and a loss of interest or pleasure in everyday activities. Oth ...
within any year-long period is 3–5% for males and 8–10% for females.
Demographic dynamics
Population studies have consistently shown major depression to be about twice as common in women as in men, although it is not yet clear why this is so.
The relative increase in occurrence is related to pubertal development rather than chronological age, reaches adult ratios between the ages of 15 and 18, and appears associated with psychosocial more than hormonal factors.
People are most likely to suffer their first depressive episode between the ages of 30 and 40, and there is a second, smaller peak of incidence between ages 50 and 60.
The risk of major depression is increased with neurological conditions such as
stroke
Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...
,
Parkinson's disease
Parkinson's disease (PD), or simply Parkinson's, is a neurodegenerative disease primarily of the central nervous system, affecting both motor system, motor and non-motor systems. Symptoms typically develop gradually and non-motor issues become ...
, or
multiple sclerosis
Multiple sclerosis (MS) is an autoimmune disease resulting in damage to myelinthe insulating covers of nerve cellsin the brain and spinal cord. As a demyelinating disease, MS disrupts the nervous system's ability to Action potential, transmit ...
and during the first year after childbirth.
The risk of major depression has also been related to environmental stressors faced by population groups such as war combatants or physicians in training.
It is also more common after cardiovascular illnesses, and is related to a poor outcome of cardiovascular diseases.
Studies conflict on the prevalence of depression in the elderly, but most data suggest there is a reduction in this age group. Depressive disorders are more common in urban than in rural populations and, in general, the prevalence is higher in groups with adverse socio-economic factors (for example in homeless people).
Data on the relative prevalence of major depression among different ethnic groups have reached no clear consensus. However, the only known study to have covered dysthymia in the US specifically found it to be more common in
African and
Mexican American
Mexican Americans are Americans of full or partial Mexico, Mexican descent. In 2022, Mexican Americans comprised 11.2% of the US population and 58.9% of all Hispanic and Latino Americans. In 2019, 71% of Mexican Americans were born in the Unite ...
s than in
European American
European Americans are Americans of European ancestry. This term includes both people who descend from the first European settlers in the area of the present-day United States and people who descend from more recent European arrivals. Since th ...
s.
Projections indicate that depression may be the second leading cause of life lost after
heart disease
Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina pectoris, angina, myocardial infarction, heart attack), heart failure, ...
by 2020.
In 2016, a study, published by JAMA Psychiatry, and written by Charlotte Wessel Skovlund, found an association between
hormonal contraception
Hormonal contraception refers to birth control methods that act on the endocrine system. Almost all methods are composed of steroid hormones, although in India one selective estrogen receptor modulator is marketed as a contraceptive. The original ...
and depression.
By country and category
Age-standardised disability-adjusted life year
A disability-adjusted life year (DALY) is a measure of overall disease burden, representing a year lost due to ill-health, disability, or early death. It was developed in the 1990s as a way of comparing the overall health and life expectancy of ...
(DALY) rates per 10,000 inhabitants in 2017.
See also
*
Prevalence of mental disorders
References
{{reflist
Major depressive disorder
Depression