Elevated CRP, HSV-1 exposure linked to reduced cognitive function schizophrenia patients
MedWire News: Elevated C-reactive protein (CRP) levels and exposure to herpes simplex virus type 1 (HSV-1) are associated with significantly reduced cognitive function in patients with schizophrenia, research shows.
"In addition to genetic factors, infectious and inflammatory processes have been identified as potential contributing factors to disease etiology and pathogenesis [in schizophrenia]," explain Faith Dickerson (Sheppard Pratt Health System, Baltimore, Maryland, USA) and team.
They add that previous studies have suggested an association between exposure to HSV-1 and cognitive deficits in schizophrenia, as well as between elevated CRP levels and the severity of cognitive symptoms in patients with the condition.
To investigate further, the team studied 588 individuals with schizophrenia (62% men) who were aged between 18 and 65 years.
Blood samples from the participants were assessed for HSV-1 antibodies and CRP levels using enzyme immunoassay.
Cognitive functioning and psychiatric symptoms were assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the Positive and Negative Syndrome Scale (PANSS), respectively.
In total, 217 patients had normal CRP levels (<5.0 µg/mL) and were HSV-1 seronegative, 109 had an elevated CRP levels (≥5.0 µg/mL) and were HSV-1 seronegative, 163 had a normal CRP levels and were HSV-1 seropositive, and 99 had elevated CRP levels and were HSV-1 seropositive.
After accounting for age, gender, race, education, recent drug/alcohol use, and diabetes, the researchers found that patients in the CRP elevated/HSV-1 positive group had the poorest RBANS scores, followed by patients in the CRP normal/HSV-1 positive group.
There was no significant difference in RBANS scores between patients in the CRP elevated/HSV-1 negative group and those in the CRP normal/HSV-1 negative group.
Patients in the CRP elevated/HSV-1 positive group were 2.35 times more likely to have a RBANS score of 60 or less, indicating reduced cognitive function, than those in the CRP normal/HSV-1 negative group, the researchers note.
HSV-1 exposure and CRP levels were not associated with symptom severity on the PANSS.
Dickerson and team conclude in the journal Schizophrenia Research: Elevated levels of CRP and exposure to HSV-1 are associated with the severity of cognitive impairment in schizophrenia.
"These findings indicate that infection and inflammation may play a major role in the cognitive deficits associated with schizophrenia."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010
By Mark Cowen