Experts say presenteeism - being physically present at work but mentally absent and unproductive, comes at a greater economic cost than absenteeism. In South Africa the cost of mental health-related presenteeism has been estimated at over five-thousand US dollars per employee annually versus about eight-hundred-and-fifty-thousand per employee annually for absenteeism. For more on this issue as the country marks Corporate Mental Health Week, here's Professor Renata Schoeman Head of MBA Healthcare Leadership at Stellenbosch Business School.