Ever notice how some people never seem to come down with colds? Perhaps you’ve attributed it to the fact that they don’t have young children, who are typically crawling with germs being around other kids who don’t wash their hands well or at all, for that matter.

Or perhaps you’ve attributed it to their diet. After all, studies show that people who consume diets high in vitamin C and zinc are more resistant to cold symptoms (beatniks will say otherwise, pointing to their own flawed studies that claim to show no link toward cold resistance and vitamin C supplementation).

But have you considered what his or her temperament is like? Is he an upbeat bloke or is she a negative ninny? Is he a Killjoy Joe or is she a Sanguine Sally? A 2003 study published in the journal Psychosomatic Medicine suggests that one’s mood has a lot to do with cold susceptibility.

Researchers from Carnegie Mellon University interviewed approximately 350 people to get a sense of their attitudes on life and their general dispositions. In addition to this, they had each of the participants “snort,” for lack of a better term, a strain of rhinovirus, a frequent cause for the common cold in adults, 30 to 35 percent of the time, in fact (there are over 200 viruses linked to the common cold).

What the researchers found was that those people who were not as upbeat or happy about life, based on how they responded to the interview questions that assessed their emotional state, were three times more likely to come down with cold symptoms after inhaling the rhinovirus. The researchers also reported that the dour folk were more likely to complain of their symptoms compared to the upbeat, optimistic hombres.

This makes a lot of sense when you stop and think about it. Happy dispositions tends to breed happiness. People want to be around others who bring them up, not down. When you’re down, you let things bother that shouldn’t. Happy people roll with the punches. Contrary to what the unhappy say, happy people receive just as many difficulties in life; they’re just better able at casting off hardships, staying on the straight and narrow path of optimism. And the same standard seems to apply to their casting off cold symptoms – not letting cold symptoms bring them down.

A very wise man I know says that negativity is like bad breath – it stinks and it repels others. The only thing that is attracted to it is negativity and all that’s associated with it. Happiness is the toothpaste to negativity - it not only cleans out the bad but helps prevent it from returning.

Happiness is the cold medicine everyone should be taking regular doses of.