Don't let the weather get you down

Seasonal affective disorder is a form of depression triggered by the seasonal switch. Abi Jackson went to learn more about SAD.

Many will have felt down in the dumps too, the grisly weather and long, dark nights taking their toll, counting down the days until spring, when everything will be cheerier, brighter, more fun.

But when does a touch of winter blues become full-blown seasonal affective disorder (SAD)?