The term business cycle (or economic cycle or boom-bust cycle) refers to economy-wide fluctuations in production, trade and economic activity in general over several months or years in an economy organized on free-enterprise principles.
The business cycle is the upward and downward movements of levels of GDP (gross domestic product) and refers to the period of expansions and contractions in the level of economic activities (business fluctuations) around its long-term growth trend.
The Great Depression was a severe worldwide economic depression in the decade preceding World War II. The timing of the Great Depression varied across nations, but in most countries it started in 1930 and lasted until the late 1930s or middle 1940s. It was the longest, most widespread, and deepest depression of the 20th century.
In the 21st century, the Great Depression is commonly used as an example of how far the world's economy can decline. The depression originated in the U.S., after the fall in stock prices that began around September 4, 1929, and became worldwide news with the stock market crash of October 29, 1929 (known as Black Tuesday).
Major depressive disorder (MDD) (also known as clinical depression, major depression, unipolar depression, or unipolar disorder; or as recurrent depression in the case of repeated episodes) is a mental disorder characterized by a pervasive and persistent low mood which is accompanied by low self-esteem and by a loss of interest or pleasure in normally enjoyable activities. This cluster of symptoms (syndrome) was named, described and classified as one of the mood disorders in the 1980 edition of the American Psychiatric Association's diagnostic manual. The term "depression" is ambiguous. It is often used to denote this syndrome but may refer to other mood disorders or to lower mood states lacking clinical significance. Major depressive disorder is a disabling condition that adversely affects a person's family, work or school life, sleeping and eating habits, and general health. In the United States, around 3.4% of people with major depression commit suicide, and up to 60% of people who commit suicide had depression or another mood disorder.
The diagnosis of major depressive disorder is based on the patient's self-reported experiences, behavior reported by relatives or friends, and a mental status examination. There is no laboratory test for major depression, although physicians generally request tests for physical conditions that may cause similar symptoms. The most common time of onset is between the ages of 20 and 30 years, with a later peak between 30 and 40 years.
The Great Depression began in August of 1929, when the United States economy first went into an economic recession. Although the country spent two months with declining GDP, it was not until the Wall Street Crash of October, 1929 that the effects of a declining economy were felt, and a major worldwide economic downturn ensued. The market crash marked the beginning of a decade of high unemployment, poverty, low profits, deflation, plunging farm incomes, and lost opportunities for economic growth and personal advancement. Although its causes are still uncertain and controversial, the net effect was a sudden and general loss of confidence in the economic future.
The usual explanations include numerous factors, especially high consumer debt, ill-regulated markets that permitted overoptimistic loans by banks and investors, and the lack of high-growth new industries, all interacting to create a downward economic spiral of reduced spending, falling confidence, and lowered production.
Comparisons between the Great Recession and the Great Depression explores the experiences in the United States, United Kingdom and Ireland.
On April 17, 2009, head of the IMF Dominique Strauss-Kahn said that there was a chance that certain countries may not implement the proper policies to avoid feedback mechanisms that could eventually turn the recession into a depression. "The free-fall in the global economy may be starting to abate, with a recovery emerging in 2010, but this depends crucially on the right policies being adopted today." The IMF pointed out that unlike the Great Depression, this recession was synchronized by global integration of markets. Such synchronized recessions were explained to last longer than typical economic downturns and have slower recoveries.
Economic history is the study of economies or economic phenomena in the past. Analysis in economic history is undertaken using a combination of historical methods, statistical methods, and by applying economic theory to historical situations and institutions. The topic includes business history, financial history and overlaps with areas of social history such as demographic history and labor history. Quantitative (econometric) economic history is also referred to as Cliometrics.