ATD effects on pain thresholds, pain ratings, and affective state
depression, pain
HEAT
With regard to pain thresholds, we investigated ATD effects on two types of pain thresholds, namely heat as well as pressure pain thresholds. Using two different types of experimental pain modalities allows for assessing how reliable 5-HT effects are across two different pain modalities that partially target different nociceptor populations. Whereas heat stimuli mainly activate skin nociception, pressure stimuli target both skin and to a greater degree deep tissue nociceptors (Kosek et al. Besides pain thresholds which target more the lower range of pain sensitivity, we also assessed pain intensity ratings of supra-threshold heat stimuli. We found that ATD also had no effect on pain intensity ratings of these stimuli. The supra-threshold intensities were tailored to the individual pain threshold (+ 3 °C) and were on average rated as eliciting moderate pain sensations. Considering supra-threshold pain intensities, previous ATD studies found reduced tolerance thresholds after ATD in two cases (Martin et al. We also assessed the effect of ATD on mood and situational pain catastrophizing as indicators of potential changes in affective states. Again, no effect of ATD was found which is in accordance with previous findings, demonstrating that the effect of ATD on affective states seems negligible in healthy individuals with no history of depression (Young 