Is your cat giving you road rage?

    20 October 2016

    Do you suffer from road rage? I do. My-mother always told me that the most effective-tactic in the face of a vicious, spluttering fellow motorist was to blow kisses. Unfortunately, I seem to more frequently employ the characteristics of the vicious splutterer than the kiss-blower.

    Research has recently come to light that could serve to explain the behaviour of those who also lose their temper over Sunday drivers. Earlier this year, the Journal of Clinical Psychiatry issued a report finding that those that fall victim to temper loss behind the wheel are more than twice as likely to be infected by a-parasite called Toxoplasma gondii, which causes a disease called toxoplasmosis.

    I’ll come back to the road rage later… first let us consider T. gondii. The first thing to know is that it is more common than you think. In fact, it is estimated that around 30 per cent of us in the UK are infected by it, along with more than 60 million people in the USA. You may have heard the advice that pregnant women should stay away from cat litter, and this guidance stems from the dangers of toxoplasmosis. The parasite is generally thought to be otherwise relatively benign, although the psychiatry journal’s findings will undoubtedly lead to further study.

    People infected by T. gondii usually show no effects. Occasionally, cases are diagnosed as a result of flu-like symptoms such as tender lymph nodes or aching muscles, but this is rare. However, adults with low immune systems, or who have recently had chemotherapy, are more susceptible to acute toxoplasmosis. The symptoms of this are more aggressive and it can cause permanent damage to the brain — but such cases are extremely infrequent.

    The parasite can live on humans and all other warm-blooded animals but is thought to breed only on domestic cats. And the most common means of transmission to humans is via ingestion of contaminated cat faeces. This can arise more often than you might suspect, via hand-to-mouth contact. There are risk factors in gardening, eating raw vegetables grown on infected soil, cleaning a cat’s litter box or having contact with a children’s sandpit. Toxoplasmosis can also be transmitted by eating raw or-partially cooked meat or using contaminated cutlery.

    The parasite is extremely dangerous to pregnant women, increasing the likelihood of miscarriage and stillbirth, but there are a range of treatments for those infected, pregnant or not. The two most popular are antimalarial medication and antibiotics.

    So there you have it. A relatively innocuous parasite thought to infect nearly a third of us, most often caused by exposure to cat faeces. It seems like a bit of a stretch from there to road rage, but that’s where the Journal of Clinical Psychology report comes in. It reported that 22 per cent of adults suffering from Intermittent Explosive Disorder (IED) were infected with T. gondii, compared with only 9 per cent in a control group with no psychiatric history. Road rage is largely considered to be caused by IED, described by the NHS as ‘a behavioural disorder characterised by brief episodes of anger and aggression’ that ‘usually starts in late childhood’. The Mayo Clinic, a prominent group of American hospitals, also lists domestic abuse, temper tantrums and ‘throwing or breaking objects’ as culminations of IED, further explaining that ‘these intermittent, explosive outbursts can cause you significant distress,-negatively impact your-relationships, work and school, and they can have legal and financial consequences’.

    So the more hot-headed among us are more likely to be infected by T. gondii — what of those who have fallen victim to it? I spoke to Kate, who was diagnosed with the infection in her-twenties after eating-infected raw food while camping in the Sinai desert. Kate, who also suffers from cyclothymia, a mild form of bipolar disorder, remembers her experience well: ‘I had very swollen glands and lymph nodes that stuck out of my neck. They were huge. At the time I wasn’t diagnosed with toxoplasmosis. It was a long struggle to get the-diagnosis, because initially the health professionals feared I had leukemia.’ The initial stages of the infection soon accelerated, and Kate got worse. ‘I ended up having to take a lot of time off work. I was sleeping about 14 hours a day, my skin hurt all over and I was terribly low and anxious. And that didn’t go away.’

    However, it was the combination of toxoplasmosis and mental health problems that proved most toxic. ‘It was a real battle trying to get anyone to take me seriously. Because I had a history of mental illness the doctors presumed my low ebb was purely down to the cyclothymia.’

    Even after her diagnosis, Kate says she was ‘never, ever’ told of a connection between toxoplasmosis and mental health, but with the benefit of hindsight, she is convinced that they were strongly linked.-‘Certainly, as I recall it, when I had toxoplasmosis, the mental health problems cranked up a notch,’ she says, recalling an ‘acute rage’. She adds: ‘Toxo, I am quite convinced, contributed to an increase in the darkness in my head.’

    And what of the long-term effects? ‘The thing with toxo is that it isn’t really talked about, although there have been murmurs of links between toxo and schizophrenia for some time. I couldn’t get my GP to give me any advice on how to combat it. I couldn’t get anyone to take me seriously. There was a charity called the Toxoplasmosis Trust that I came across quite by mistake when walking on my lunchbreak and they were the only people I could talk to who didn’t think I was utterly bonkers.’

    Of the latest information linking toxoplasmosis to road rage, Kate says: ‘I think it’s a little bit silly perhaps. A lot of people carry toxoplasmosis and a lot of people are angry and stressed or have mental health problems. The road-rage findings are attention-grabbing headlines, but more needs to be done for both afflictions: toxo and mental health.’

    Kate’s view is that of a victim, not a medical professional, but many professionals agree that the links between mental health and toxoplasmosis warrant further investigation. One such is Paul Ewald of the University of Louisville, an evolutionary biologist specialising in the evolution of infectious disease.

    ‘We know that toxoplasma alters behaviour and it gets in the brain, so it’s not really surprising that it would have these kind of [road rage] effects,’ he told Spectator Health. ‘Toxoplasma is now very strongly associated with the development of schizophrenia. And if toxoplasma is altering schizophrenic behaviours, it’s unlikely to be altering just one set of characteristics — it’s very likely to be messing up other parts of human behaviour.’

    While recognising that toxoplasmosis-undoubtedly alters the prey host (the infected human), Ewald believes the road-rage finding is, at present, a little far-fetched. ‘It’s possible that this particular variation of aggressiveness could be part of human selection, but it could very well be a parasite altering-behaviour and enhancing rage. I think we are just beginning to investigate this problem. We need to look at the whole spectrum of changes in behaviour because toxoplasma evidently causes infections and alters the brain.’

    More research on the relationship between toxoplasmosis and mental health in general is clearly necessary. Until then, keep blowing kisses.



    Share of the UK population estimated to be infected with the parasite Toxoplasma gondii

    60 million

    Number of people in the USA thought to be infected


    In tests, proportion of ‘Intermittent Explosive Disorder’ sufferers with the same parasite