Around 30% of those would suffer chronic mental health problems, Jacques Snyman, product development director at Agility Global Health Solutions, said.

The information was released on World Mental Health Day yesterday.

"Acting as a trigger to severe psychiatric conditions such as depression, stress can also lead to acute psychotic episodes," Snyman said.

The SA Stress and Health study ranked the country as the seventh highest in the world for the prevalence of mood disorders and sixth for the prevalence of anxiety disorders.

Businesses should be concerned about these figures, Snyman said.

An Australian study found that stress-related absenteeism and "pre-absenteeism" cost that country's economy about R115-billion a year. For employers, the direct cost was estimated at about R78-billion