Monday, June 8, 2015

The mysterious link between cat bites and depression

Every cat owner knows that these lovely animals are very independent-minded and often quite capricious. They also possess sharp claws and teeth and frequently don't hesistate to use them.
A cat bite is not only painful - it can potentially have serious consequences. Cats are carnivores and harbor some very nasty bacteria in their mouths. A cat bite often leads to a tissue infection, necessitating antibiotic treatment. In rare cases such infections can actually prove fatal.

However, it seems that the vision of a painful, pus-filled wound is not the only reason to fear a cat's teeth. American researchers have discovered an astonishing link between cat bites and human depression.
In a recent data mining study, performed in Michigan on a population of 1.3 million patients, depression was found in 41.3% of patients with cat bites and only 28.7% of those with dog bites. (Overall there were 750 patients with cat bites, 1,108 with dog bites, and approximately 117,000 patients with depression.) Furthermore, 85.5% of those with both cat bites and depression were women, compared to 64.5% of those with dog bites and depression.

It gets even better. Based on over 10 years of data, if a woman presented to the University of Michigan Health System with a cat bite that was serious enough to warrant medical attention, there was a 47.0% chance that she will also be given a diagnosis of depression at some point in her life, compared to 24.2% of men presenting with a similar bite. The gender difference was still present but smaller for dog bites: if a woman presented with a dog bite, there was a 35.8% chance of having depression compared to 21.1% of men. The highest depression rate was for patients who had both a dog bite and a cat bite, with nearly half (47.8%) having depression, all of them women.

The high prevalence of depression in patients who were bitten by a cat, especially women, suggests that screening for depression might actually be appropriate in patients who present to a clinical provider with a cat bite.

Interestingly, the most common types of animal bites in the ICD E906.3 category (which comprises bites of animals other than dogs, rats, snakes, lizards and arthropods) were cats (n = 701, 80.9%), squirrels (n = 45, 5.2%), bats (n = 20, 2.3%) and raccoons (n = 17, 2.0%), although a wide variety of other animals were also mentioned, including moles, monkeys and mice, as well as parrots, pigs, piranhas, and prairie dogs. The majority (58.8%) of cat bites in the study were inflicted by the patients’ own cat, including 56.1% among those who had depression. Being bitten by a stray or feral cat was least common (15.7% of all bites, and 15.2% of bites among those with depression).

As yet, no causative link is known to explain this puzzling statistical association between depression and cat bites. Researchers speculate that, perhaps, Toxoplasma gondii infection (known to be spread by cats, and linked to brain pathologies and personality changes) may play a role. Alternatively, domesticated cats may become more aggressive in response to changes in their owners' mental state and behavior. There is also some evidence that cat owners tend to be more neurotic - and, hence, more prone to depression - than dog owners. Overall, the relationship between cats and human mental illness apparently needs to be investigated further.

Image courtesy of dan at

Hanauer DA, Ramakrishnan N, Seyfried LS. (2013) Describing the Relationship between Cat Bites and Human Depression Using Data from an Electronic Health Record. PLoS One. 2013; 8(8): e70585.


  1. An excerpt from a much lengthier post on all of the 3dozen+ deadly zoonotic diseases that these free-roaming vermin cats are spreading to all other animals and humans today:

    ... Then there’s cats’ most insidious disease of all, their Toxoplasma gondii parasite that cats spread through their feces into all other animals. This is how humans get it in their dinner-meats, cats roaming around stockyards and farms (herbivores can contract this parasite in no other way). This is why cats are routinely destroyed around gestating livestock or important wildlife by shooting or drowning them. So those animals won’t suffer from the same things that can happen to the fetus of any pregnant woman. (Miscarriages, still-births, hydrocephaly, and microcephaly.) It can make you blind or even kill you at any time during your life once you’ve been infected. It becomes a permanent lifetime parasite in your mind, killing you when your immune system becomes compromised by disease or chemo and immunosuppressive therapies. It can last over a year in any soils or waters and not even washing your hands or garden vegetables in bleach will destroy the oocysts. During dry-spells of weather (or inside low-humidity homes) when the oocysts become dessicated you can even contract T. gondii by just inhaling the air wherever any cats have defecated and the oocysts have become airborne/aerosolized. Contrary to cat-lickers’ self-deceptive myths, a cat can become reinfected many times during its life and spread millions of oocysts each time. It’s now linked to the cause of autism, epilepsy, schizophrenia, memory-loss, and brain cancers; as well as increasing the suicide rate in women almost 2-fold even though they’ve never suffered from any mental or emotional health issues previously. This parasite is also killing off rare and endangered marine-mammals (all the way up to rare whales) along all coastlines, along with inland river-otters, from cats’ T. gondii oocysts in run-off from the land, the oocysts surviving even in saltwater. A catastrophic ecological disaster of multi-continent-sized proportions worse than any oil-spill that has ever existed or could even be imagined.

    Its strange life cycle is meant to infect rodents. Any rodents infected with it lose their fear of cats and are attracted to cat urine. http://scitizen.Com/neuroscience/parasite-hijacks-the-mind-of-its-host_a-23-509.html

    Cats attract rodents to your home with their whole slew of diseases (like The Plague from rats and fleas, many people have died from cat-transmitted Plague in the USA already, it is alive and well and being spread by cats today). If you want rodents in your home keep cats outside of it to attract diseased rodents to your area. I experienced this phenomenon (as have many others), and all rodent problems disappeared after I shot and buried every last one of hundreds of cats on my lands. Much better NATIVE rodent predators returned to my lands, rather than these man-made cats that were just attracting more rodents.

    1. Another interesting experiment. They wanted to find out if dogs could possibly transmit cat-shat Toxoplasma gondii oocysts. A dog infected with T. gondii from a source-cat cannot. The oocyst stage of this parasite's life-cycle by which cats spread their parasite into all other animals is 100%-dependent on cat-physiology as its primary reproductive host. But if dogs ingest oocyst-laden cat-feces then dogs can pass the oocysts produced by cats & their common brain-hijacking parasite. http://www.ncbi.nlm.nih.Gov/pubmed/9477489?dopt=Abstract&holding=f1000,f1000m,isrctn

      It is interesting to note that these Toxoplasma gondii oocysts shed by cats can even survive the hydrochloric stomach acids for the duration that they remain in a mammal's digestive tract. And then they doubt my words when I tell them of the studies where they found that this parasite's oocysts (seeds) can even survive washing your hands in bleach. You could wash your hands and garden vegetables in hydrochloric acid and digestive enzymes for the same duration that food remains in an animal's digestive tract and even that won't destroy it. Your hands would be dissolved into a digestible pulp long before you could kill the Toxoplasma gondii oocysts.

      Yeah, "basic hygiene" is going to keep your kids safe from going blind sometime during their life, becoming autistic, schizophrenic, get ADHD, suffer from epilepsy, get brain-cancers, debilitating depressions, suffer from memory-loss, commit unexplained suicides, suffer from other neurological illnesses, or die if they ever require any immunosuppressive therapies or contract any immunity-compromising diseases during their lifetime if they had ever played in a sandbox that a neighbor's cat has defecated in.

      Go ahead everyone, drink the cat-lickers' Kool-Aid.

      Someone who will save the life of one of their clearly expendable vermin cats over yours is not to be trusted by any other human alive on this planet. Even cat-lickers can't trust their fellow cat-lickers to save each others' lives when it comes right down to it. Truth is, they'd even rather that their own family and friends die (if they have any) than any of their deadly disease-infested cats. Sociopaths and psychopaths, one and all, right to their very cores.