Depression From Cat Bites?

depression
As health records in developed countries are largely electronic, researchers have been using a method called data mining to find previously unknown or even unconceived of correlations. Sometimes the correlation is vague at best, and can be disregarded as being caused by an obvious factor not present in electronic health records (EHRs).The peer-reviewed journal PLoS ONE (Public Library of Science) published an article in August 2013 about a correlation found between cat bites and depression, a correlation that was higher across both genders, but even more so among women. The correlation was found using data mining.

To more closely study such a possible relationship, three scientists, David A. Hanauer, Naren Ramakrishnan and Lisa S. Seyfried, accessed the EHRs of 1.3 million patients. They referenced for numbers of those who had presented with cat bites, those who had presented with dog bites, and those who had been diagnosed with or treated for depression. What they found was surprising.

Of the 1.3 million, approximately 117,000 fit into the category of people having suffered from or suffering from depression. Of these, 1,108 had reported dog bites, and 750 had been bitten by cats. It is very important to note that, in general, depression is observed in 8.8% of the adult population.

Of the 117,000 people suffering from depression in this study, the gender difference was roughly a 55/45 split, female to male. Researchers acknowledge however that the greater number of women with the mental illness could be attributable to the fact that more women than men seek medical attention.

In terms of depression as related to animal bites in this group, the highest rate of the mental illness occurred in the group that had experienced both a cat bite and a dog bite. This group was small, however, at 23, and they were all women. The group exhibiting the next highest ratio was those bitten by cats (750 persons), who experienced a 41.3% rate of depression, as opposed to the general populace rate of just under 9%. Lastly, the group bitten by dogs exhibited a 28.7% rate of the mental illness. All of these rates are substantially higher than is normal across the general population.

Of the population that had crossover between cat bites and depression, 85.5% were women, whereas of the dog bite victims, only 64.5% were female. The latter figure is close to being on par with the gender instances of this particular mental illness across a global population. In other words, being bitten by a dog did not seem to raise a woman’s chances of also experiencing depression, whereas being bitten by a cat did. Scientists involved in the study acknowledge there is currently no clear reason for this statistic as the research came out of data mining and was not aimed specifically at finding causative results. Further and more specific studies would need to be done to determine what, if any, relation exists between being bitten by a cat and experiencing the mental illness.

Still, the numbers show a distinct correlation between cat bites and depression, especially where women are concerned. In fact, results of this study suggest that screening for the mental illness may be warranted when any patient, male or female, presents with a cat bite, as the corresponding correlation is so high. For females particularly, researchers say that a woman’s chances of developing the illness at some point in her life if bitten by a cat is, as shown from these numbers, a 47% chance.

Previous studies have begun looking at a link between a bacteria found in cat feces, Toxoplasma Gondii, and schizophrenia, as well as suicide.

By Julie Mahfood

Follow Julie Mahfood on Twitter @JulieWrites2

Sources:

PLoS ONE
Mayo Clinic
Smithsonian Mag

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