title: IL-6 and TNF-α in unmedicated adults with ADHD: Relationship to cortisol awakening response.
abstract: There is preliminary evidence that the immune system's cytokines may have impact on ADHD in children. Nevertheless, studies exploring the possible role of pro-inflammatory cytokines in adults with ADHD are lacking. This study aimed to assess differences in serum IL-6 and TNF-α between patients and controls and their possible relationship to resting cortisol. 108 adults with ADHD (DSM-IV), 44 inattentive and 64 combined, age ranging between 18 and 55 years, and 27 healthy controls were included. Major psychiatric disorders and organic comorbidities were excluded. Serum samples for IL-6 and TNF-α and salivary samples to assess cortisol awakening response were collected on the same day. Analysis of variance was applied to study differences in IL-6 and TNF-α between groups. Pearson correlations were used to study associations between IL-6, TNF-α, and CAR. There were no significant differences in serum IL-6 or TNF-α levels between patients and controls or between combined and inattentive patients. Negative associations between IL-6 (r=-0.386, p=0.020), TNF-α (r=-0.372, p=0.023) and cortisol awakening response were found in the inattentive subtype, whereas no association was seen in the combined subtype. A negative correlation between IL-6 and cortisol was also present in the control group (r=-0.44, 0.030). The peripheral pro-inflammatory markers, IL-6 and TNF-α, do not appear to be primarily involved in ADHD in adults, although the role of other inflammatory markers cannot be ruled out. The differences regarding the association between IL-6 and TNF-α and morning cortisol response suggest possible underlying neurobiological differences between the inattentive or combined patients that merit further studies.
authors.affiliation: Department of Psychiatry, Hospital Universitari Vall d'Hebron, CIBERSAM, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain; Biomedical Network Research Center on Mental Health (CIBERSAM), Madrid, Spain. Electronic address: mcoromin@vhebron.net.
authors.forename: M
authors.initials: M
authors.lastname: Corominas-Roso
authors.affiliation: Institut de Neurociéncies, Red de Trastornos Adictivos (RTA) and CIBERSAM, Unitat de Fisiologia Animal, Department de Biologia Cel·lular, Fisiologia I Immunologia, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Armario
authors.affiliation: Department of Psychiatry, Hospital Universitari Vall d'Hebron, CIBERSAM, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain.
authors.forename: G
authors.initials: G
authors.lastname: Palomar
authors.affiliation: Department of Psychiatry, Hospital Universitari Vall d'Hebron, CIBERSAM, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Corrales
authors.affiliation: Institut de Neurociéncies, Red de Trastornos Adictivos (RTA) and CIBERSAM, Unitat de Fisiologia Animal, Department de Biologia Cel·lular, Fisiologia I Immunologia, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Carrasco
authors.affiliation: Department of Psychiatry, Hospital Universitari Vall d'Hebron, CIBERSAM, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Richarte
authors.affiliation: Department of Biochemistry, Hospital Universitari Vall d'Hebron, Barcelona, Catalonia, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Ferrer
authors.affiliation: Department of Psychiatry, Hospital Universitari Vall d'Hebron, CIBERSAM, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain; Biomedical Network Research Center on Mental Health (CIBERSAM), Madrid, Spain; Department of Psychiatry and Legal Medicine, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Casas
authors.affiliation: Department of Psychiatry, Hospital Universitari Vall d'Hebron, CIBERSAM, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain; Biomedical Network Research Center on Mental Health (CIBERSAM), Madrid, Spain; Department of Psychiatry and Legal Medicine, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: Ramos-Quiroga
mesh_terms: D000293:Adolescent; D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000097:blood* / Q000503:physiopathology; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis*; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010913:Pituitary-Adrenal System / Q000503:physiopathology; D012463:Saliva / Q000737:chemistry; D014409:Tumor Necrosis Factor-alpha / Q000097:blood*; D055815:Young Adult
chemical_list: D015415:Biomarkers; C508600:IL6 protein, human; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D006854:Hydrocortisone
keywords: ADHD; Attention deficit hyperactivity disorder; Cortisol; Cytokines; Il-6; TNF-α