A Complex Relationship Among the Circadian Rhythm, Reward Circuit and Substance Use Disorder (SUD)

Saptadip Samanta,1 Debasis Bagchi,2,3 Mark S Gold,4 Rajendra D Badgaiyan,5 Debmalya Barh,6 Kenneth Blum7– 12 1Department of Physiology, Midnapore College, Midnapore, West Bengal, 721101, India; 2Department of Biology, College of Arts and Sciences, Adelphi University, Garden City, NY, USA and Department of Psychology, Gordon F. Derner School of Psychology, Adelphi University, Garden City, NY, USA; 3Department of Pharmaceutical Sciences, College of Pharmacy, Southern University, Houston, TX, 77004, USA; 4Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; 5Department of Psychiatry, Case Western Reserve University School of Medicine, Cleveland, OH, USA; 6Centre for Genomics and Applied Gene Technology, Institute of Integrative Omics and Applied Biotechnology, Nonakuri, Purba Medinipur 721172, West Bengal, India; 7Division of Addiction Research & Education, Center for Sports, Exercise, and Mental Health, Western University Health Sciences, Pomona, CA, 91766, USA; 8Institute of Psychology, Eotvos Loránd University, Budapest, 1053, Hungary; 9Department of Psychiatry, Wright State University Boonshoft School of Medicine and Dayton VA Medical Center, Dayton, OH, 45435, USA; 10Department of Psychiatry, University of Vermont, Burlington, VT, 05405, USA; 11Division of Nutrigenomics, The Kenneth Blum Behavioral & Neurogenetic Institute, Austin, TX, 78701, USA; 12Department of Molecular Biology, Adelson School of Medicine, Ariel University, Ariel, IsraelCorrespondence: Saptadip Samanta; Debasis Bagchi, Email [email protected]; [email protected]; [email protected]: The human brain not only controls the various physiological functions but is also the prime regulator of circadian rhythms, rewards, and behaviors. Environmental factors, professional stress, and social disintegration are regarded as the initial causative factors of addiction behavior. Shift work, artificial light exposure at night, and chronic and acute jet lag influence circadian rhythm dysfunction. The result is impaired neurotransmitter release, dysfunction of neural circuits, endocrine disturbance, and metabolic disorder, leading to advancement in substance use disorder. There is a bidirectional relationship between chronodisruption and addiction behavior. Circadian rhythm dysfunction, neuroadaptation in the reward circuits, and alteration in clock gene expression in the mesolimbic areas influence substance use disorder (SUD), and chronotherapy has potential benefits in the treatment strategies. This review explores the relationship among the circadian rhythm dysfunction, reward circuit, and SUD. The impact of chronotherapy on SUD has also been discussed.Keywords: SCN, circadian rhythm dysfunction, melatonin, cortisol, drug addiction