Self-Critical Perfectionism Predicts Lower Cortisol Response to Experimental Stress in Cfs Patients

[Hip]

But they don't. They ask about behavior, hence are inappropriate.

Less accurate perhaps, if the questionnaire questions are referring to behavior rather than how you feel.

It's hard to say though, because I think people vary greatly in their introspection ability. I know some people who seem almost oblivious to their own mental states, and others who are very aware of them.

If you ask someone with poor introspection abilities how they feel, you may get inaccurate results. Whereas if you ask them what they do (ie, how they behave), then they may give you a more accurate account. I think this point was mentioned earlier.