Impact of stimulation dose and personality on autonomic and psychological effects induced by acupuncture.

Acupuncture has been shown to exhibit distinct effects on the autonomic nervous system. We tested whether the autonomic and psychological response to acupuncture depends on the stimulation dose and the personality of the treated subjects. 52 healthy subjects were randomized to receive either low dose (one needle at point Hegu bilaterally) or high dose (additional 4 needles at non-acupoints bilaterally) acupuncture stimulation after stratification according to their personality to "reduce" or "augment" incoming stimuli. Outcomes were changes of electrodermal activity (EDA), high frequency component of heart rate variability, heart rate, mean arterial blood pressure, respiration rate and subjective parameters for psychological well being and perceived intensity of needling. Electrodermal activity increased during needle insertion and decreased under baseline when subjects were resting with the needles in the body for 20 min. The initial EDA increase was significantly (GEE ANCOVA p<0.001) more pronounced during high dose stimulation and independent of personality. All other physiological parameters did not show any significant group effect. Strong stimulated augmenters perceived acupuncture most painful and increased with their psychological activation after the acupuncture session in contrast to the other groups, which showed a decrease of activation in the pre-post comparison (overall group effect p=0.032). The data indicate that during needle insertion high dose acupuncture stimulation leads to a higher increase of sympathetic nerve activity than low dose stimulation independent of personality. After needle insertion subjects who tend to augment incoming stimuli might show a lack of psychological relaxation when receiving high dose stimulation.