Thank you for your reply.
I am reasonably well aware of my own 'mental health'. I have suffered from obsessive complusive disorder (manifested by checking) and severe (at times suicidal) depression. I am extremely well at the moment. I have done 4 years of psycotherapy and I am on 5 x 75 mg of Efexor now. When I am over tired or stressed at work I sometimes start to 'check' again but I can usually bring this under control quite rapidly. I can tell when critical reflection is becoming for me negative and I call a halt to it at this point and engage in an activity which I am good at and which gives me satisfaction and a sense of achievement.
My question now is if I am encouraging OTHERS to engage in critical reflection, what are the signs/clues I can look for that the process is becoming negative for them? Naturally, if I suspected a problem similar to the ones I experienced I would encourage them to see a professional.