IL-6 and TNF-α in unmedicated adults with ADHD: Relationship to cortisol awakening response

M. Corominas-Roso, A. Armario, G. Palomar, M. Corrales, J. Carrasco, V. Richarte, R. Ferrer, M. Casas, J. A. Ramos-Quiroga

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20 Citations (Scopus)


© 2017 Elsevier Ltd 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.
Original languageEnglish
Pages (from-to)67-73
Publication statusPublished - 1 May 2017


  • ADHD
  • Attention deficit hyperactivity disorder
  • Cortisol
  • Cytokines
  • Il-6
  • TNF-α


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