Infants And Children Exposed To Household Pet Dogs Less Likely To Develop Schizophrenia As Adults – Study

Schizophrenia is a chronic mental condition that affects the way an individual thinks, behaves, expresses feelings, and relates with others.

Individuals who are schizophrenic find it difficult to cope with daily living in society and often out of touch with reality.

Such individuals may be withdrawn and frightened and may have a combination of delusions (beliefs that are not based on reality) and hallucinations (seeing and hearing things that do not exist).

Schizophrenia can be extremely disabling and treatment is often lifelong. Early treatment helps to put conditions under control and can help prevent complications.

There are a series of studies that link both genes and environmental factors to the development of schizophrenia. There are also evidence from the literature that finger the immune system in modulating the neurodevelopmental pathway of the brain – and environmental factors have been established to influence the immune system.

Now, a new study is exploring the role of pets (environmental factors) in modulating brain development. And the results are intriguing.

The study found that children who were exposed to household dogs early in life were less likely to develop schizophrenia. To measure this, the scientist used Cox proportional model to generate a hazard ratio, to find the relationship between the age of first pet exposure and the diagnosis of schizophrenia.

A hazard ratio is a time-series measurement that compares how often certain events ( in this instance, exposure to pets and development of schizophrenia) happen in a study group with the frequency of the same events in the control population. A hazard ratio of 1 suggests no difference between the two populations (study and control), less than 1 means the risk of developing schizophrenia is lower and vice-versa for greater than 1.

The study, provided by John Hopkins Medicine, found a statistically significant relationship that when children were exposed to household pet dogs before celebrating their 13th birthday, they were 24% less likely to develop schizophrenia as adults.

According to WHO, some 20 million people worldwide suffer from schizophrenia. Applying the findings from this study then, about 4.8 million cases of schizophrenia worldwide could have been prevented by early exposure to pet dogs, if the hazard ratio was a true reflection of the risk of developing the disorder.

Some facts about schizophrenia

  • Schizophrenia is one of the top 15 causes of disability worldwide.
  • Rate of suicide higher than the general population.
  • Schizophrenics suffer more premature deaths than the general population
  • The financial burden of schizophrenia is far higher than those of other mental disorders in society.

Interestingly, the study findings were more pronounced among those exposed to pet dogs at birth and before the age of 3 years, suggesting that the earlier the exposure, the more the correlation.

“We found that exposure to a household pet dog was associated with a significantly decreased hazard of having a subsequent diagnosis of schizophrenia (Hazard Ratio .75, p < .002) Furthermore, a significant decreased relative risk of schizophrenia was detected following exposure at birth and during the first years of life.”

According to the Insurance Information Institute, about 85 million families own pets in the US. Disaggregation shows that the majority of the pets are dogs, using data from the American Pet Products Association’s 2019-2020 National Pet Owners Survey.

Source: American Pet Products Association’s 2019-2020 National Pet Owners Survey.

With a growing interest in pets worldwide, the benefits have now extended beyond mere companionship and security. It may be then that the more the population own household pet dogs, the less the likelihood of schizophrenia in society.

The researchers cautioned though, that there were limitations to the study and more investigations were needed to unearth the reasons behind the findings.

The researchers thus concluded:

“In our study population, exposure to a household pet dog at birth and during the first three years of life is associated with a significantly decreased hazard and relative risk of a subsequent diagnosis of schizophrenia. Trends in associations between childhood household exposure to a pet cat and relative risks of schizophrenia and bipolar disorder were also detected. These associations may be due to socio-demographic, neuro-immune, or other biological factors or combinations of factors. An understanding of the mechanisms underlying these associations could provide insights into the role of environmental exposures as risk factors for these disorders and inform appropriate interventions.”

Samuel Abiona

Samuel Abiona

Samuel Abiona is a medical doctor by training and a writer by passion. Samuel holds a postgraduate degree in Public Health. He believes that communicating medical knowledge goes beyond writing technical reviews. Samuel thus uses his expertise in public health and health systems research to transmit technical information for both academic and general audience. Please email to contact this author directly or use the contact page and your information will be passed on to him.