In 2016, Denmark was ranked as the happiest nation globally, even though it is dark for 16 hours a day in midwinter.

The annual World Happiness Report assesses criteria such as per capita income, life expectancy, people's freedom to make life decisions, generosity, social support, and government and business corruption.

The Danes focus on the small things that really matter, such as quality time with friends and family, and enjoying the good things in life. Hygge (pronounced 'hooga') is translated as 'cosiness', but Danes argue it is more than that. It is togetherness and relaxation, an indulgence and a comfort.

Work is also a great way to beat gloominess. But how work is done, with whom, and in what circumstances can create or destroy happiness.

There are three different types of happiness measures:

1. How we experience positive emotions.
2. How we experience negative emotions.
3. Life evaluations (how happy we are with our lives as a whole.)

Brain scans show that volunteers who rated highly on happiness surveys had more grey matter mass in the precuneus, involved in self-reflection and consciousness.

• Researchers analysed the DNA of people around the world and found three genetic variants for happiness. Two of the variants are linked with differences in the symptoms of depression.
• Another paper suggests that the DNA of people who regard themselves as happy is more likely to contain a specific gene variant.
• Other research shows that national levels of happiness depend on how close we are genetically to the Danes.