In the present study, a subjectively intense odor had no effect on the dream emotions. Our previous studies revealed that preferred and familiar odors induced negative dreams. Odor pleasantness (hedonic strength) and familiarity ratings correlated with the intensity ratings; therefore, we hypothesized that a subjectively intense odor might induce negative dreams and that high sensitivity would correlate with a more negative odor, similar to preferred and familiar odors. However, this hypothesis was not supported.

— Read more in Subjectively intense odor does not affect dream emotions during rapid eye movement sleep at Nature.