Friends Provident has produced a guide for employers aimed at helping to reduce absence in the workplace and the estimated £26bn a year cost to British business.
The guide, produced by mental health charity Mind, is designed to help employers understand the nature of mental health problems.
It also includes guidance on how to encourage a mentally healthy working environment.
The provider said it hopes the guide will explode some of the myths that continue to cloud understanding of mental health in today's workplace.
Mental health problems accounted for 29% of all group income protection claims paid out by Friends Provident in 2009, and the provider is urging employers to consider how best to address this long-term cause of absence.
A report from the Chartered Institute of Personnel and Development (CIPD) shows one in five employers reported an increase in mental health problems amongst their employees (including anxiety and depression) in the last 12 months, indicating the growing incidence of this condition in light of the current economic environment.
Paul Farmer, chief executive of Mind explains: "Mental health problems in the workplace are very common, yet despite the fact that 1 in 6 people of working age will have some kind of mental health issue, few employers have a mental health policy or know how to support staff to stay in work successfully when they're going through a rough patch.
"Badly managed mental distress costs British business an estimated £26 billion a year, a figure which could be reduced by a third with better mental health and well-being support for staff."
Declan White, group protection marketing manager at Friends Provident, adds: "It's no secret that growing numbers of us will experience mental health problems in our lifetime.
"But despite the increased awareness, many employers are still in the dark about how best to support staff to help them either remain in or return to work following any mental health problems."
