The purpose of this study is to evaluate whether medications used in peri-procedural clinical settings can modulate drug liking.

Specifically, we aim to measure differences in drug liking with a VAS (0 - 100) questionnaire. Additionally, we will monitor neural activity recording a frontal electroencephalogram (EEG) to detect changes in brain signals associated with opioid drug effects. By comparing behavioral and neurophysiological data across treatment and control groups, this study seeks to explore the therapeutic potential of this medication.

Inclusion Criteria:

• American Society of Anesthesiologists (ASA) physical status classification of I, II or III
• Candidates who are expected to receive fentanyl up to 3 mcg/kg IBW for their scheduled for surgery or procedure

Exclusion Criteria:

• Craniofacial abnormalities
• Known or suspected difficult intubation or mask ventilation
• Known or suspected need for rapid sequence induction and intubation
• Allergies or hypersensitivities to amisulpride or fentanyl
• Clinically significant pulmonary disease, such as chronic obstructive lung disease requiring long-term oxygen therapy, or other conditions that, in the study team's judgment, may increase the risk of severe respiratory depression with opioid administration
• History of long QT syndrome
• Any heart rhythm other than normal sinus rhythm (including but not limited to atrial fibrillation, atrial flutter, paced rhythms, ventricular tachycardia, or any supraventricular tachycardia)
• History of Torsades de Pointes
• History of psychosis
• History of movement disorders e.g. Parkinson's Disease
• Past chronic use of anti-psychotics
• Current use of amisulpride, droperidol, levodopa, lithium, clozapine, metoclopramide, benzodiazepines
• Current use of opioids
• History of opiate abuse within the last 3 years
• Known or suspected severe chronic pain condition that require use of opiates or limit daily activities
• History of pheochromocytoma
• History of concomitant prolactin-dependent tumors e.g. prolactinoma, breast cancer
• Pregnancy or nursing
• Failure to satisfy the investigator of fitness to participate for any other reason