Schizophrenia, infection and executive function

People with schizophrenia often suffer from cognitive deficits including executive dysfunction which shows itself in the form of impaired reasoning and problem-solving abilities and is associated with the more severe and disabling forms of the condition as well as poorer functional outcomes. There is increasing evidence that infections caught during pregnancy, in particular toxoplasmosis and influenza, can cause schizophrenia and researchers from Columbia University in New York studied 26 people with schizophrenia to see if there was a link between prenatal infection and poor executive functioning. People who had been exposed to infections in the womb made significantly more errors on the tests and took more time to finish them.

Brown, Alan S. ... [et al] - Prenatal exposure to maternal infection and executive dysfunction in adult schizophrenia American Journal of Psychiatry June 2009, 166(6), 683-690

Toxoplasmosis and schizophrenia

Several research studies have shown a link between toxoplasmosis - a minor disease cause by a parasite called toxoplasma which is chiefly, though not solely, carried by cats - and schizophrenia. Schizophrenia is also thought to be linked to high levels of a neurotransmitter (chemical signaller) called dopamine in the brain. Researchers at Leeds University have found that the parasite's genetic make-up includes an enzyme that aids in the production of dopamine. The author of the study, Dr. Glenn A. McConkey, said that it was still too early to suggest changes to the way that schizophrenia is treated but that it would be a good idea to screen people for the condition as part of their initial assessment.

You can find out more about this research at

http://uk.reuters.com/article/healthNews/idUKTRE52H6IP20090318?feedType=RSS&feedName=healthNews

Toxoplasma and schizophrenia

A study of 712 U.S. military personnel has found that those people who had been exposed to a parasite called toxoplasma gondii had a 24% higher risk of developing schizophrenia than their unaffected colleagues. Previous studies have shown a link between toxoplasma antibodies and schizophrenia but it has proved difficult to tell which of the diseases came first. Because the U.S. military routinely tests its active personnel for toxoplasma and stores the results in a central repository researchers were able to determine the time line between infection and a diagnosis of schizophrenia. Toxoplasma gondii is a common parasite carried by cats and farm animals and most infections with it occur early in life following an exposure to the parasite in cat faeces or undercooked beef or pork. Infections rarely cause symptoms but the parasite remains in the body and can reactivate after lying dormant for years. Not everyone who was infected with toxoplasma went on to develop schizophrenia suggesting that its effect can be affected by individual differences between its human hosts.

You can find out more about this research at

http://psychcentral.com/news/2008/01/17/parasite-may-lead-to-schizophrenia/1798.html