How cat scratches can help understand schizophrenia

Do you remember our article about schizophrenia and cat litter? Well, we’re gonna talk about cats again, because if I tell you right away that this article is about Bartonella, you might not even read it. Don't worry, I get you. However, this little bacteria is way more interesting than it sounds.

So, now that I have your attention, Bartonella is commonly associated with the so-called "cat scratch disease" (or CSD), but it can also be carried by dogs or other mammals. This bacteria, just like our furry friends, is really fascinating, but definitely not as cute, mainly because it “hides” in blood vessels and is able to mimic chronic illnesses. It has been identified in a number of cases of chronic illnesses that the medical community previously hadn’t been able to attribute to a specific cause.

So far, we knew that there are almost 30 known species of the bacteria, and 13 of those have been found to infect human beings. But before your give your cat away, don’t worry: according to the Center for Disease Control and Prevention, most cat scratches do not result in cat scratch disease and the disease is more likely to affect children less than 15 years old. Just in case, here is all you need to know about preventing CSD.

However, in March 2019, a team of researchers from the North Carolina State University found a surprising case of Bartonella mimicking… schizophrenia.

It all started more than a year ago, when an adolescent started presenting sudden onset psychotic behavior. Although he was diagnosed as having schizophrenia, he didn’t respond to conventional treatments. For over 18 months, he was seen and treated by numerous specialists and therapists before a physician recognized lesions on the patient’s skin that are often associated with Bartonella. The patient tested positive for the infection, was treated for it and recovered completely. So why is this so interesting (except for the scenario of a Doctor House episode)?

Although he was diagnosed as having schizophrenia, he didn’t respond to conventional treatments.

Schizophrenia is a chronic mental disorder that can take several aspects, and is often misunderstood and/or a source of stigmatization. It is mostly characterized by distortions in thinking, perception, emotions, language, sense of self and behaviour. According to the National Institute of Mental Health in the US, the person can experience a wide array of symptoms like hallucinations, movement disorders, trouble focusing or paying attention, or even (to a certain extent of course) reduced feelings of pleasure in everyday life. Today, the WHO reports that schizophrenia affects around 20 million people worldwide. It is associated with considerable disability and may affect educational and occupational performance.

One more thing about schizophrenia, and maybe the most important: we don’t know exactly how or why people have it. We know though that it’s definitely not a choice and that symptoms generally start between 16 and 30 years of age. Researchers have not identified a single factor, but believe that it’s a complex connection between genes, environmental, psychological factors as well as a possible imbalance in the chemical reactions of the brain. It is however treatable with the appropriate medication and psychosocial support, even when it is caused by a vicious bacteria like Bartonella.

One more thing about schizophrenia, and maybe the most important: we don’t know exactly how or why people have it.

We know though that it’s definitely not a choice

In short, the case study published in the Journal of Central Nervous System Disease is another piece of the puzzle to understand the roots of schizophrenia: the symptoms can actually be the result of a bacterial infection. But what about other mental disorders? How often are infections involved with psychiatric disorder?

We don’t know yet, but this case for sure opened a door: researchers are now starting to look at things like infections' role in Alzheimer’s disease.

• Insane's article about the story of Dévi and his schizophrenia

• Our other article about cat litter and schizophrenia

• Insane's tips about how to find a psychiatrist in France (in French only)