Depressiveness and neuroticism in Bartonella seropositive and seronegative subjects – preregistered case-controls study (data)

Several recent studies have
demonstrated the association of cat-related injuries with major depression and
with depressiveness in the general population. It was suggested that
cat-scratch disease, the infection with the bacterium Bartonella henselae, can
be responsible for the observed association. However, no direct evidence for
the role of the Bartonella infection
in this association has been published until now. In this preregistered
case-controls study performed on 250 healthy subjects tested earlier for the
presence of anti-Toxoplasma IgG
antibodies, we searched for the positive association between presence of
anamnestic anti-Bartonella IgG
antibodies and depressiveness measured with Beck II inventory, depression subscale
of neuroticism measured with N-70 questionnaire, and self-reported health
problems. We found that that Bartonella-seropositivity
was positively correlated with Beck depression only in Toxoplasma-seronegative men and negatively correlated with health
in Toxoplasma-seronegative women. Bartonella
seropositivity expressed protective effects against Toxoplasma seropositivity-associated increased neuroticism in men
while Toxoplasma-seropositivity
expressed protective effects against Bartonella
seropositivity-associated health problems in women. A comparison of the patterns
of association of mental and physical health problems with Bartonella seropositivity and with reported cat-related injury
suggests that different factor, possibly infection with different pathogen transmitted
by cat related-injuries than the Bartonella
henselae, is responsible for the
observed association of cat related-injuries with depressiveness and major
depression. The existence of complex interactions between Bartonella seropositivity, Toxoplasma
seropositivity, and sex also suggest that the effect of symbionts on the host’s
phenotype must by always studied in the context of other infections, and
separately for men and women.