While the high prevalence of mental illness in workplaces is more readily documented in the literature than it was ten or so years ago, it continues to remain largely within the medical and health sciences fields. This may account for the lack of information about mental illness in workplaces (Dewa et al. Healthcare Papers 5:12-25, 2004) by operational managers and human resource departments even though such illnesses effect on average 17 % to 20 % of employees in any 12-month period (MHCC 2012; SAMHSA 2010; ABS 2007). As symptoms of mental illness have the capacity to impact negatively on employee work performance and/or attendance, the ramifications on employee performance management systems can be significant, particularly when employees choose to deliberately conceal their illness, such that any work concerns appear to derive from issues other than illness (Dewa et al. Healthcare Papers 5:12-25, 2004; De Lorenzo 2003). When employee non-disclosure of a mental illness impacts negatively in the workplace, it presents a very challenging issue in relation to performance management for both operational managers and human resource staff. Without documented medical evidence to show that impaired work performance and/or attendance is attributable to a mental illness, the issue of performance management arises. Currently, when there is no documented medical illness, performance management policies are often brought into place to improve employee performance and/or attendance by establishing achievable employee targets. Yet, given that in any twelve-month period at least a fifth of the workforce sustains a mental illness (MHCC 2012;

Purpose – This paper aims to describe how performance management may inadvertently expose employees with a hidden mental illness to disciplinary procedures. Design/methodology/approach – It outlines how to manage possible cases of hidden mental illness to ensure HR specialists are providing valuable resources in this area, rather than pursuing a performance-management plan that may be inappropriate and/or ineffectual. Findings – It highlights the importance of putting into place policies to deal with the high numbers of employees who make the conscious choice to keep their mental disorder hidden. Practical implications – It explains that stigma and shame will often cause employees to remain silent about such illnesses, but when the symptoms of hidden mental disorders affect attendance and/or performance, the organization can consider adopting policies to deal with this area rather than ignoring it. Social implications – It reveals that, on average, 20 per cent of employees attend work in any calendar year with a common mental illness. Originality/value – It provides useful guidance on dealing with mental illness, which is often hidden.

On a global scale, mental illness affects on average one in five employees in any twelve month period, and is well represented in the medical research literature as a dominant discourse. However, its presence in management and human resource management (HRM) research literature, while certainly on the rise, is less prevalent than it is in medical and related areas of research. At the same time, discussion of employee mental illness and its effects on employee performance and/or attendance, barely rates a mention in management and HRM textbooks, nor is it a common part of the curricula for university and other forms of higher education seeking to equip our future managers and HRM staff with the necessary skills and knowledge to be effective leaders. This paper will show that employee mental illness is a pervasive element of all workplaces, and as a consequence, policies to manage this phenomenon are not only vital, but overdue. Furthermore, it will be posited that this subject requires immediate inclusion in the teaching programs and textbooks of our future managers and HRM staff, and should be elevated from relative obscurity in such offerings to the status of a dominant discourse.