Half of employees have never been asked in a one-to-one with managers about stress, depression or anxiety, a survey for Bupa has found.
More than two thirds (69%) of business leaders said their organisations need to do more to prevent stress in the workplace.
Over three quarters (76%) of business leaders believed they actively encouraged managers to address and support mental health issues.
The survey was carried out in summer 2014 and surveyed 50 business leaders and 500 employees with and without mental health conditions.
The survey also found that 80% of business leaders said they have effective measures in place to tackle mental health issues while only 32% of employees who had mental health issues agreed.
The majority (60%) of employees with mental health conditions said they were not happy in their current role because of how they had been treated. And 70% did not believe there is an open culture in their organisation.
Patrick Watt, corporate director at Bupa, said: "There is a clear disconnect between what leaders believe they are doing about mental health in the workplace versus how employees feel.
"Businesses need to take action. Managers need to be trained to spot the signs and know how to support employees to get the right help.
"Employers should also take steps to help prevent mental health problems from occurring by creating an open culture and putting practices in place that support good mental wellbeing."
"Employers need to understand the business benefits and their moral responsibility for engaging with mental health and take active steps to improve employee wellbeing."
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