Centrol and peripheral correlates of anxiety: a comparative study.

Physiological measurements and mood ratings were recorded in 32 normal subjects at rest and under differing stressful conditions designed to induce anxiety. The physiological measurements were recorded simultaneously using a polygraph and on-line computer analysis; these comprised the peripheral measurements of pulse rate, skin conductance, spontaneous fluctuations in skin conductance, respiratory rate, and finger tremor, and the central measurements of resting electroencephalogram and averaged evoked potentials to an auditory stimulus. Mood rating were recorded using analogue rating scales, the 16 scores obtained being reduced to three mood factors. Correlations were calculated between the mood factors and each of the physiological measurements. The highest correlations were between the anxiety factor and the central measurements, particularly the proportion of electroencephalographic activity between 7.5 and 13.0 Hz, and the latencies of the secondary components of the evoked response. The peripheral measurements correlated rather less well with mood, but skin conductance and fluctuations in skin conductance, pulse rate, and tremor near the peak frequency of 9 Hz all correlated significantly with anxiety. Only two correlations were greater than 0.4, illustrating that no measure was a specific index of anxiety. Refinement of central rather than peripheral measurements is likely to lead to closer correlations with anxiety and other mood states.