Trigger point: Christmas and new year with PTSD – video

For veterans suffering from post traumatic stress disorder (PTSD) such as Colin and Mick, everyday life is full of sights, sounds and smells that can bring on flashbacks and nightmares. Christmas and new year can be particularly hard. Find out how the charity Gardening Leave uses horticultural therapy to help veterans recover and return to civilian life. Gardening Leave is one of nine charities in the Guardian and Observer Christmas appeal

• Click here to donate to the Guardian and Observer Christmas charity appeal

• The Guardian and Observer Christmas appeal on mental health