The effects of consent procedures on the psychophysiological assessment of anxiety: a methodological inquiry.

The present study investigated the effects of informed consent regarding upcoming, aversive stimuli on autonomic and self-report measures of anxiety. Physiological and self-report measures were recorded prior to the subject receiving information regarding the nature of the upcoming stressor (naive baseline block), following the receipt of this information (informed baseline block), during the anticipation of the stressor (anticipation block), and following the expected stressor (post-stressor baseline block). Examination of mean levels of autonomic activity during the naive and informed baseline blocks and the patterns of correlations involving those blocks indicated that the naive and informed baseline blocks were noncomparable. Implications of these findings for experimental design and clinical assessment are discussed.