Role of olfactory reactions, nociception, and immunoendocrine shifts in addictive disorders.

BACKGROUND AND OBJECTIVES: Addictive pathology is associated with nervous, immune, and endocrine shifts. Meanwhile, the nature of intersystemic relationship lying beneath addictive disorders remains unclear. The purpose of the study was to identify neuroimmunoendocrine markers of addictive disorders in male subjects defining the nature of their interaction.

METHODS: The study enrolled 69 subjects aged 18-43 years: 59 males and 10 females divided into those with addictive disorders (n = 39) and conditionally healthy subjects (n = 30). EEG testing with olfactory stimulation, olfactometric, and pressure algometric examinations was carried out. Multiplex technique was applied to determine mitogen-induced production of cytokines IL-10, IL-1, IL-1RA, IL-2, IFN-gamma, TNF-alpha. ELISA method was applied to measure serum cortisol and testosterone levels.

RESULTS: Olfactory responses to isopropanol with open eyes in addicted patients manifested as increase in alpha-rhythm and beta1-rhythm, with closed eyes presentation of this odorant was accompanied by increase of theta-rhythm in opioid-addicted patients. Male subjects with addictive disorders showed reduced alpha-rhythm in terms of olfactory stimulation with modified emotional evaluation of the odorant, deficient mitogen-induced production of IFN-gamma, and reduced pain sensitivity. Male subjects with opioid addiction had reduced beta1-rhythm in terms of olfactory stimulation, mitogen-induced production of IFN-gamma, and elevated testosterone level.

CONCLUSIONS: The findings obtained verify potential involvement of nociception, olfaction, and cytokine production in addiction pathogenesis evidencing their various roles depending on the range of psychoactive substances (PAS) and pathology progression.

SCIENTIFIC SIGNIFICANCE: The data obtained may provide background for unification of reward circuit and inhibitory control concepts in regulation of addictive behavior. (Am J Addict 2017;26:640-648).