The 68-page document aims to provide businesses with information to build a positive working environment and support employees who may already be suffering from mental health issues.
Amanda Powell-Smith, CEO of Forster, said there was a strong relationship between levels of staff wellbeing and performance, and that many employers were unaware of how to help employees who may be experiencing mental health issues.
"We know that working in PR and communications can sometimes be high pressured and we have seen that there are still many people working in the industry who do not feel supported.
"We hope that every business in the industry draws on this toolkit to develop their approaches to mental health. Taking a positive approach to mental health will bring benefits to individuals, business and society," she said.
Currently, one in six employees across all UK businesses have experienced mental health issues, according to the agency. The PR industry is above average with over a third of professionals experiencing or being diagnosed with mental health problems, according to a survey carried out by the PRCA for PRWeek in 2015.
As part of Mental Health Awareness Week 2016, which ends on Sunday, numerous organisations and individuals are working to raise awareness of the issue, including newly elected Mayor of London, Sadiq Khan.