Study reveals the key to happiness is...

We all want to be happy. But how, exactly, do you obtain it?

Well, thanks to the longest running study on long-term happiness, we now have the answer.

Harvard Medical School started the Grant Study back in 1938.

Originally analysing 268 people - including president-to-be John F. Kennedy - only 19 of the participants are still alive today.

So the scientists expanded the research to include the participants' offspring — which is now made up of 1,300 people in their 50s and 60s.

For nearly 80 years, researchers interviewed these individuals about their lives, gave them questionnaires, took brain scans and blood samples, examined their medical records, and spoke with their families.

So what is the key to long-term happiness?

Good relationships.

That's right, if you want to live an amazing life, make your relationships with others a priority.

Apparently those who maintain close relationships with their family and friends are healthier, happier, have better brain functioning, and live longer.