That said, there are some signs which it can be helpful to watch out for, which don’t require in-person contact to become apparent, and which might suggest that someone is having difficulty concentrating or could be suffering from poor mental health. These include:
Suddenly reduced or unpredictable performance
Neglect of safety advice/more accidents
Withdrawal - being difficult to reach by telephone/electronic means
High rates of sickness absence
Being short-tempered or having outbursts of anger