He has investigated neurobiological and clinical aspects of substance use disorders, in particular intoxication and withdrawal from opioids, alcohol, and cocaine, and has tested the validity of behavioral and physiologic markers of disease. Dr. Mannelli has studied opioid agonist-antagonist interactions and their role in the transition from opioid use to naltrexone treatment of opioid use disorder. At policy level, he is involved with pharmacological and public health research for a better understanding of obstacles and barriers to medically assisted treatment of opioid use disorder and other substance use disorders. In his clinical practice, he treats patients with substance use disorders and comorbid psychiatric and medical diagnoses, and he routinely performs induction to buprenorphine and naltrexone treatments.