Taking the first interview from a patient, clinicians ask questions about the way stess affect every daylife & performance. So using a short questionnaire cheking vital signs you have an indicator.
As indirect indices of stress response, you could assess changes in heart rate and galvanic skin response (GSR); these measures are used commonly in experimental stress induction procedures and drug cue-reactivity studies.
Yes, certainly! Skin resistance or galvanic responses, skin temperature (distribution changes), heart rate variability; or even echocardiographic wall motion abnormalities... or EEG frequency/spectra changes... there are many more options! For the autonomous nervous system activity, besides cortisol, alpha-amylase could also be interesting (e.g., saliva), or acteylcholin-esterase activity.
Thank you all. We are looking for physiological readings that can be taken in the field. And I was afraid that BP, heart rate, and body temp might be so affected by other factors that they would not accurately reflect stress levels?
Yes that is true. But if you take modern sensor technology with it (these sensors do not have to be so expensive - we use(d) the ones from movisens (http://www.movisens.com/en), you can sort out whether an increase in blood pressure, body temp, heart rate frequence deterioration, etc., actually is a result of mental processes (e.g., psychomental stress), or a bodily response to exercise, activity, acceleration and so on. These sensors also measure acceleration, atmospheric pressure, change of altitude, transposition.... and calculate the said stress indices!