Some QoL factors assessed in this study were not expected to be affected by the alleviation of nasal congestion. Instead, these factors were likely resolved on their own through the natural disease course, such as the ‘think clearly’ factor, which we found to significantly improve from day 3. The effect of the common cold on ‘thinking clearly’ is not well understood. However, the combined effects of sleep disruption, 40 and the underlying mechanism of inflammation may impact neurotransmitter function, 10 may cause irritability and mild cognitive impairment during a common cold episode.8,41