Persistent infection with neurotropic herpes viruses and cognitive Impairment

Calkins ME, Richard J, Edwards N, Savage RM, Allen TB, Kwentus J, McEvoy JP, Santos AB, Wiener HW, Go RCP, Perry RT, Nasrallah HA, Gur RE, Devlin B, Nimgaonkar VL: Persistent infection with neurotropic herpes viruses and cognitive Impairment.  Psychological Medicine / Volume 43 / Issue 05 / May 2013, pp 1023 1031 DOI: 10.1017/S003329171200195X, Published online: 14 September 2012

This publication examines how herpes virus infections can cause cognitive impairment during and after acute encephalitis and its relationship to schizophrenia. Environmental influences have long been suspected to contribute to the development of mental illness, for example major stressors and perinatal infections have been implicated as negative influences on early brain development and thus cognitive abilities in schizophrenia. This study looked at a large sample (1852 individuals) that included three groups: control individuals, schizophrenia patients and their non-psychotic relatives. Cognitive measures were administered with a computerized test battery that assessed thinking skills such as memory, attention and problems solving. A summary cognitive domain was developed and viral exposure was determined by antibodies to viral antigens for all three groups. Latent or persistent herpes virus infections were found to be associated with cognitive impairments regardless of mental health status. The reader of this paper will gain a better understanding of how infections that affect the brain, along with other organ systems can result in cognitive impairment. For the psychiatric community, this paper demonstrates that herpes and other viral exposures are important to cognition but not specific to schizophrenia or families with affected members.