If there are concerns about poor performance, the manager should explore whether there is a health or disability issue, including mental health, before implementing any formal performance management steps. Asking simple questions about how an employee is, and whether anything is affecting their performance can give them an opportunity to disclose a disability, mental health issue or something else going on in their lives. It may also be useful to ask about relations with colleagues.
Managers should not force someone to disclose a mental health issue, or suggest they are ill, but can explore this in a way that is not intrusive or judgemental. One way is to start from your own observations e.g. “I’ve noticed that you’ve been having a lot of headaches recently. How are you feeling?”
If the manager is aware of a mental health issue, s/he should explore possible reasonable adjustments for mental ill-health and performance should be monitored. In the small number of cases where an individual with severe mental health issues is unable to perform their role despite adjustments, HR advice should be sought.
Evidence of performance, including attendance records, should be collected, and should form the basis for an honest discussions between manager and employee. This makes it more difficult for the individual to deny the existence of any difficulties.
It may be helpful for a second person to sit in as an observer on all one-to-one meetings. A person with complex mental health issues may have difficulty in making a realistic assessment of a situation, and may fantasise about what has been said.