The kitchen of a cat hoarder/ASPCA

That crazy cat lady – yeah, you know, the one almost every community has – well, it might not be her fault.

Some new science is fingering the cats.

Yes, truly. A Tuesday study in Brain, Behavior and Science suggest cats can make you nuts.

The team of 17 Danish scientists and two colleagues from John Hopkins University and the Stanley Medical Research Institute in the U.S. use more politically  correct terms, but that’s what they say.

The problem isn’t really the cat or cats per se, it should be noted; it’s the cat crap and the parasite Toxoplasma gondii usually found therein.

T. gondii was found to have a strong association with schizophrenia, the study said.

Some have been suggesting that maybe the crazy-cat lady problem isn’t the people but the cats for some time.

“When most people hear about animal hoarding, they recall shocking news stories about the ‘crazy cat lady,'” says the website of Anxiety and Depression Society of America. “They immediately side with the animals, rarely considering the life of what led to this behavior.

“(But) the term ‘animal hoarding’ refers to the compulsive need to collect and own animals for the sake of caring for them that results in accidental or unintentional neglect or abuse. Most animal hoarders fall victim to their good intentions and end up emotionally overwhelmed, socially isolated, and alienated from family and friends.”

Social withdrawal and alienation from family and friends are key signs of schizophrenia.

Mental health infections

“In recent years there has been a growing interest in the influence of infectious agents on human behavior and mental disorders,” the new study said. “Common infectious pathogens such as T. gondii and cytomegalovirus (CMV) have been associated with psychiatric disorders, cognitive deficits, suicidal behavior, and traffic accidents.”

CMV is a form of herpes that the study observes has already been linked to “visual impairment, hearing loss or cognitive impairment. Several studies have (also) shown that infection with CMV is associated with increased risk of psychiatric disorders such as schizophrenia, bipolar disorder, and cognitive deficits.”

Looking for more definitive links between these pathogens and mental illness, the researchers turned to the Danish Blood Donor Study holding plasma and DNA samples for 110,000 people age 18 to 67.

They then began cross referencing that data with the Danish Psychiatric Central Research Register, a computerized data base that records all admissions to Danish psychiatric hospitals since 1969 and all outpatient treatment since 1995.

The Danes also do a good job of cataloging deaths, hospital admissions and traffic accidents. As a result, the scientists found a lot of data to mine. They eventually found 2,591 people with psychiatric disorders – 151 of them schizophrenics – and started looking at their blood.

“We found that individuals with a T. gondii infection had increased odds of being diagnosed with schizophrenia disorders compared to those without infection,” they wrote. “Besides schizophrenia, T. gondii infection was not statistically significantly associated with any other psychiatric disorder.”

On the other hand, CMV was not associated with schizophrenia, but it was associated with neurotic and stress-related psychiatric disorders and with suicide or attempted suicide.

“This largest to date (blood) study provides evidence that exposure to T. gondii might be a contributing causal factor for developing schizophrenia and that exposure to CMV might be a contributing causal factor for developing serious psychiatric disorders,” the scientists concluded.

They suggested a number of biochemical pathways that could link T. gondii to schizophrenia and observed that “it has been shown that schizophrenic patients treated with anti-psychotic drugs have lower levels of antibodies to T. gondii compared to untreated schizophrenic patients. One could argue that the effect of anti-psychotic drugs in schizophrenic patients may be partly due to the inhibition of T. gondii activity.”

That said, they admitted that the Danish blood donor population is skewed toward upper-income Danes and married males.

“We cannot rule out that socio-economic factors could potentially account for part or all of the observed causal effect,” they wrote, although that appears unlikely among the generally affluent.

The costs of poverty

Socio-economic factors or SES (socio-economic status), as it is more commonly called, have been shown to have all sorts of as yet unexplained effects on health and never in a good way.

For instance, fetal alcohol syndrome (FAS) –  a serious problem in Alaska – has been linked to low SES in study after study.

“One classic study of the influence of SES in the United States found that the risk of bearing a child with FAS was 15.8 times higher for women of lower SES even with comparable drinking levels,” a 2011 study in Alcohol Research noted.

“In most population-based studies, women with FASD children have lower levels of education and more frequently are unemployed or underemployed,” the authors of that study wrote.

“An overarching trait that may modify or enhance all of the above cofactors of risk is ‘weathering.’ Weathering is a concept put forth to explain the cumulative effect of poor living conditions, inadequate nutrition, and high levels of stress on childbearing.”

How these same SES issues relate to mental health is unclear, but they are unlikely to make people healthier.

The authors of what will be called the “cat-crap study” for ease of reference admitted “we did not control for socio-economic factors, which may have an effect on health outcome,” and yet they still found evidence pathogens appeared to be causing mental illness.

“Our findings support the growing scientific evidence linking pathogenic infection with serious psychiatric disorders,” they concluded. “Routinely screening for T. gondii and CMV in populations with psychiatric disorders may identify novel stratification groups, which can be used to target treatment  in combination with analysis of genetic risk factors. Likewise, targeting T. gondii or CMV infections can provide novel therapeutic approaches as well as potential biomarkers to identify individuals at increased risk. A detailed understanding of the origin, mechanisms and outcomes of these pathogenic infections in relation to psychiatric disorders, self-violence and risk-taking behavior is necessary in order to improve detection and treatment.”

They stopped short of suggesting getting rid of cats in favor of a dog, but that might not be a bad idea either.

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