An inconclusive study does not find Toxoplasma gondii infection causes schizophrenia as is reported on many websites this morning.

Toxoplasma gondii cyst in mouse brain.

The online newspapers and even online science journals are misrepresenting the conclusions of another study which seeks to find a link between the parasitic protozoan toxoplasma gondii and psychiatric disorders in people.

For instance, IFL Science’s headline boldly and brazenly declares: Biggest Study To Date Finds Link Between Cat Pee And Schizophrenia.

However, the study itself (which we can’t be sure has been carried out soundly – see quote below) concludes in the first lines: T. gondii infection might be a contributing causal factor for schizophrenia.

Below is a comment from Jane:

“My in house, red cell serologist read the paper, so did I. His verdict is that it shows all that is wrong with science. I agree.

EG. Extrapolating connections to theoretical ‘psychiatric’ disease/self harming behaviours from populations who are at least 50% carriers of CMV/TG, is nothing more than a wild stab in the dark. Hilarious in its ineptitude, at best.

It is a pick & mix, disorganised piece of junk. It identifies what it wants to prove, then, rather than try to disprove it, via thorough method & practice, it scrambles desperately to grasp connection to an exploratory, unproven hypothesis. This is micro-combing of data. It is bullshit.

The ‘scientists’ who authored this junk are clinging to their security of tenure. White knuckles, desperate.

Science is the big embarrassment on this one.”

Inconclusive study on T. gondii

Therefore the findings of the study are inconclusive. They do not find a causal link. My message to website reporters is to do better please and don’t undermine the reputation of the domestic and feral cat. Also IFL Science carelessly refers to ‘cat pee’ when they should refer to ‘cat poo’.

The cat is a definitive host of the Toxoplasma gondii protozoan (shed in faeces) and therefore if reporters misrepresent the conclusions of studies in this way they are hurting the status of the domestic cat. This can lead to retaliation against stray cats by irresponsible and ignorant people. There is already enough cat abuse in the world. Please don’t encourage more gratuitous violence against innocent animals.

I’d argue that the study entitled: “Large-scale study of Toxoplasma and Cytomegalovirus shows an association between infection and serious psychiatric disorders” [link], might be flawed anyway.

For instance, it may be the case that people with psychiatric disorders are more likely to seek the comfort of a domestic cat and be careless about cleaning the cat’s litter tray. This may expose the person far more to Toxoplasma oocysts which in turn could lead to a higher incidence of people with mental health problems having toxoplasmosis. This is just a crude example. There are many other variables which could mask the conclusion.