title: Inflammatory markers are associated with decreased psychomotor speed in patients with major depressive disorder.
abstract: Previous data have demonstrated that administration of inflammatory cytokines or their inducers leads to altered basal ganglia function associated with reduced psychomotor speed. Decreased psychomotor speed, referred to clinically as psychomotor retardation, is a cardinal symptom of major depressive disorder (MDD) and has been associated with poor antidepressant treatment response. We therefore examined the association between plasma inflammatory markers and psychomotor speed in ninety-three un-medicated patients with MDD. Psychomotor speed was assessed by a range of neuropsychological tests from purely motor tasks (e.g. movement latency and finger tapping) to those that involved motor activity with increasing cognitive demand and cortical participation (e.g. Trails A and Digit Symbol Substitution Task (DSST)). Linear regression analyses were performed to determine the relationship of inflammatory markers and psychomotor task performance controlling for age, race, sex, education, body mass index, and severity of depression. MDD patients exhibited decreased psychomotor speed on all tasks relative to normative standards. Increased IL-6 was associated with decreased performance on simple and choice movement time tasks, whereas MCP-1 was associated with decreased performance on the finger tapping task and DSST. IL-10 was associated with increased performance on the DSST. In an exploratory principle component analysis including all psychomotor tasks, IL-6 was associated with the psychomotor speed factor. Taken together, the data indicate that a peripheral inflammatory profile including increased IL-6 and MCP-1 is consistently associated with psychomotor speed in MDD. These data are consistent with data demonstrating that inflammation can affect basal ganglia function, and indicate that psychomotor speed may be a viable outcome variable for anti-inflammatory therapies in depression and other neuropsychiatric disorders with increased inflammation.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30329, United States. Electronic address: drgolds@emory.edu.
authors.forename: David R
authors.initials: DR
authors.lastname: Goldsmith
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30329, United States.
authors.forename: Ebrahim
authors.initials: E
authors.lastname: Haroon
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30329, United States.
authors.forename: Bobbi J
authors.initials: BJ
authors.lastname: Woolwine
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30329, United States.
authors.forename: Moon Y
authors.initials: MY
authors.lastname: Jung
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30329, United States.
authors.forename: Evanthia C
authors.initials: EC
authors.lastname: Wommack
authors.affiliation: Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL 33136, United States; Research Service, Bruce W. Carter VA Medical Center, Miami, FL, United States.
authors.forename: Philip D
authors.initials: PD
authors.lastname: Harvey
authors.affiliation: Department of Psychology, Emory University, Atlanta, GA 30322, United States.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Treadway
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30329, United States; Winship Cancer Institute, Emory University, Atlanta, GA 30322, United States.
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Felger
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30329, United States; Winship Cancer Institute, Emory University, Atlanta, GA 30322, United States.
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Miller
mesh_terms: D000328:Adult; D018932:Chemokine CCL2 / Q000097:blood*; D016207:Cytokines / Q000097:blood*; D003865:Major Depressive Disorder / Q000097:blood* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood*; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011597:Psychomotor Performance / Q000502:physiology*; D055815:Young Adult
chemical_list: C111835:CCL2 protein, human; D018932:Chemokine CCL2; D016207:Cytokines; C508600:IL6 protein, human; D015850:Interleukin-6
keywords: Chemokines; Cognition; Cytokines; Depression; Inflammation; Psychomotor speed