PLOS ONE: Describing the Relationship between Cat Bites and Human Depression Using Data from an Electronic Health Record

Data mining approaches have been increasingly applied to the electronic
health record and have led to the discovery of numerous clinical
associations. Recent data mining studies have suggested a potential
association between cat bites and human depression. To explore this
possible association in more detail we first used administrative
diagnosis codes to identify patients with either depression or bites,
drawn from a population of 1.3 million patients. We then conducted a
manual chart review in the electronic health record of all patients with
a code for a bite to accurately determine which were from cats or dogs.
Overall there were 750 patients with cat bites, 1,108 with dog bites,
and approximately 117,000 patients with depression. Depression was found
in 41.3% of patients with cat bites and 28.7% of those with dog bites.
Furthermore, 85.5% of those with both cat bites and depression were
women, compared to 64.5% of those with dog bites and depression. The
probability of a woman being diagnosed with depression at some point in
her life if she presented to our health system with a cat bite was
47.0%, compared to 24.2% of men presenting with a similar bite. The high
proportion of depression in patients who had cat bites, especially
among women, suggests that screening for depression could be appropriate
in patients who present to a clinical provider with a cat bite.
Additionally, while no causative link is known to explain this
association, there is growing evidence to suggest that the relationship
between cats and human mental illness, such as depression, warrants
further investigation.