The association among smoking, HSV-1 exposure, and cognitive functioning in schizophrenia, bipolar disorder, and non-psychiatric controls.
Previous investigations have found that smokers with schizophrenia demonstrate reduced performance on cognitive tasks compared to non-smokers. However previous studies have not taken into account other environmental factors associated with cognitive functioning such as exposure to Herpes Simplex Virus type 1 (HSV-1). We examined these factors in a sample consisting of individuals with schizophrenia (n=773), bipolar disorder (n=493), or controls without a psychiatric disorders (n=548). Participants were assessed on a cognitive battery, the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and had a blood sample drawn to measure seropositivity to HSV-1. Within each group linear regression models were constructed to determine whether cigarette smoking and HSV-1 seropositivity were jointly associated with cognitive functioning after adjusting for relevant covariates. Within the schizophrenia group, the effect size of lower total cognitive score was -0.279 (p<0.0001) for individuals who were both smokers and HSV-1 seropositive and a significant effect was found in all cognitive domains. The odds of being in the highest quartile of RBANS Total score were significantly lower for smokers (OR=0.58, 95% CI 0.41, 0.82, p=0.002). Smoking was not as consistently associated with levels of cognitive functioning in the bipolar disorder or the non-psychiatric control group. While experimental studies show that nicotine transiently improves functioning on sensory gating and attention tasks known to be deficient in schizophrenia, long-term nicotine exposure via smoking appears to have an adverse effect on cognitive functioning.
Sheppard Pratt Health System, Baltimore, MD, USA. Electronic address: fdickerson@sheppardpratt.org.
Faith
F
Dickerson
Sheppard Pratt Health System, Baltimore, MD, USA.
Maria B
MB
Adamos
Sheppard Pratt Health System, Baltimore, MD, USA.
Emily
E
Katsafanas
Sheppard Pratt Health System, Baltimore, MD, USA.
Sunil
S
Khushalani
Sheppard Pratt Health System, Baltimore, MD, USA.
Andrea
A
Origoni
Sheppard Pratt Health System, Baltimore, MD, USA.
Christina L G
CLG
Savage
Schroeder Consulting, LLC, Ellicott City, MD, USA.
Jennifer
J
Schroeder
Sheppard Pratt Health System, Baltimore, MD, USA.
Lucy A B
LAB
Schweinfurth
Sheppard Pratt Health System, Baltimore, MD, USA.
Cassie
C
Stallings
Sheppard Pratt Health System, Baltimore, MD, USA.
Kevin
K
Sweeney
Johns Hopkins School of Medicine, Baltimore, MD, USA.
Robert
R
Yolken
D000328:Adult; D000914:Antibodies, Viral / Q000097:blood; D001714:Bipolar Disorder / Q000150:complications* / Q000523:psychology / Q000821:virology; D003071:Cognition; D003072:Cognition Disorders / Q000150:complications / Q000821:virology; D005260:Female; D018259:Herpesvirus 1, Human / Q000276:immunology; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D011618:Psychotic Disorders / Q000150:complications* / Q000523:psychology / Q000821:virology; D012044:Regression Analysis; D012559:Schizophrenia / Q000150:complications* / Q000821:virology; D012565:Schizophrenic Psychology; D012907:Smoking / Q000523:psychology
D000914:Antibodies, Viral
Bipolar disorder; Cognitive; Herpes virus; Nicotine; Schizophrenia; Smoking