By Lydia Nuzum As the holiday season comes into full swing, many are gearing up for a joyous Christmas - but not everyone is in a festive mood. For many, Christmas and its accompanying celebrations can be a source of stress and even sadness - demands like shopping, baking, planning, cleaning and entertaining can cause stress levels to spike, and factors like Seasonal Affective Disorder, isolation or the death of a loved one may lead to depression.