BBC NEWS | Health | Happiness 'rubs off on others'

BBC NEWS | Health | Happiness 'rubs off on others': "Happiness is infectious and can 'ripple' through social groups, according to US researchers.

A study of 5,000 adults suggests a person's happiness is dependent on the happiness of those around them.

A friend who becomes happy and lives less than a mile away increases your likelihood of happiness by 25%, the British Medical Journal reported.

But the mood of work colleagues did not have an effect, the Harvard Medical School-led study found."