In one session subjects were exposed to: (1) androstadienone diluted in a vehicle while breathing unscented air and (2) androstadienone in vehicle while breathing a pleasant odorant. In another session they were exposed to: (1) vehicle and unscented air and (2) vehicle and a pleasant odorant. Phasic contact heat was used to induce pain.
Planned comparisons confirmed that, in the absence of pain, androstadienone improved mood only in women, while the pleasant odorants improved mood for all subjects. However, these positive mood changes did not persist with the introduction of pain. Consistent with the absence of positive mood changes, pain unpleasantness was not modulated. Unexpectedly, the presence of androstadienone increased perceived pain intensity especially in women, suggesting an effect of androstadienone on pain perception, independent of mood changes. Heightened attentional state may be responsible.