The 19 unhappiest countries in the world

Residents of Cambodia expressed little faith in its politics, according to the results of the report.

The Southeast Asian country's current Prime Minister Hun Sen reclaimed power in 2013, despite mass protests and claims of fraud, according to the BBC.

Poll respondents from Angola reported a very low level of freedom to make life choices.

Residents' life expectancy is also low. On average, men live to just 50 years, while women live to 53 years, according to the World Health Organization.

This African nation has a low GDP of just $938 (approximately £654), according to figures from the World Bank.

Despite declaring independence from Sudan in 2011, unrest has continued in this African nation. The 2013-2015 civil war left 2.2 million people without homes, according to the BBC.

Respondents reported low levels of social support from others.

According to the World Health Organization, male residents of Chad live on average up to the age of 51, while women living there reach the age of 53.

The country is also impoverished, experiences violence, and has poor social and health conditions, according to the BBC.

Burkina Faso has experienced military coups and frequent droughts, according to the BBC. The landlocked country has a GDP of $1,620 (£1,128), shown by data from the World Bank.

Uganda declared independence from Britain in 1962, and has since experienced a military coup and violent dictatorship. Internationally, the country's government has a reputation for its homophobic views of the LGBT community, according to the BBC.

Average life expectancy levels aren't especially high, either. Figures from the World Health Organization show that men tend to live up to the age of 57, and women up to the age of 61.

This Middle Eastern nation suffers from ongoing conflict, in the throes of a civil war. Terrorist groups like Islamic State are also active there.

This island nation off Africa's southeast coast has experienced several violent coups and political instability, according to its profile on the BBC.

The report suggests that residents have little freedom to make choices.

Many Tanzanians live below the poverty line, according to the BBC. World Bank figures show that the country has a GDP of $2,538 (£1,762).

Liberia's economy is one of the weakest in the report with a GDP of $841 (£548), according to the World Bank.

While much of the country's population is unemployed and illiterate, the BBC reports that thousands of Liberians were killed by Ebola between 2013 and 2016.

Guineans are among the poorest people in West Africa, while the country's economy has also suffered from the volume of refugees that have come from neighbouring countries Liberia and Sierra Leone, according to the BBC.

Rwanda's 100-day genocide of 1994, in which thousands of people were killed and many left without homes, still bears on the country today.

Benin produces the largest amount of cotton in Africa, according to the BBC, but that hasn't helped its economy. Data from the World Bank shows that the country's GBP is $2,030 (£1,409).

Residents' life expectancy is also low; men are expected to live until the age of 57, and women until the age of 60, according to figures from the World Health Organization.

War in Afghanistan has obliterated much of the country's infrastructure and displaced many of its citizens. Afghan respondents also reported low levels of social support from others.

Togo has a weak economy and is dependent on foreign aid, according to the BBC. The West African nation is known for crime relating to the poached ivory trade.

Residents of Togo interviewed for the survey reported meagre levels of freedom to make choices.

Syria's ongoing civil war has killed over 250,000 of its residents, according to the BBC, while millions of refugees have fled the country to escape the conflict. 72% of Syrians don't have access to clean drinking water, while 2 million children are out of education, according to a United Nations press statement issued in December.

Syrian respondents reported a tiny amount of freedom to make choices.

People in Burundi, the unhappiest nation in the world, have extremely little freedom to make their own choices. The country's economy is also incredibly poor, with a GDP of $770 (£535).

Residents don't live long, either. According to life expectancy data from the World Health Organization, men live for an average of 54 years, while women live for 58 years.