ACTH	Adrenocorticotropic Hormone
BBB	Blood–Brain Barrier
CAGE	Cut down, Annoyed, Guilty, Eye-opener
cAMP	Cyclic Adenosine Monophosphate
CNS	Central Nervous System
COX-2	Cyclooxygenase-2
CRF	Corticotropin-Releasing Factor
CRP	Cancer-Related Pain
EMA	European Medicines Agency
FPS	Facial Pain Scale
HPA	Hypothalamic–Pituitary–Adrenal
IARC	International Agency for Research on Cancer
IASP	International Association for the Study of Pain
i.v.	Intravenous
MAT	Medication-Assisted Treatment
MCLS	Mesocorticolimbic System
NMOU	Non-Medical Use of Opioids
NSAIDs	Nonsteroidal Anti-Inflammatory Drugs
NRS	Numeric Rating Scale
OIH	Opioid-Induced Hyperalgesia
ORT	Opioid Risk Tool
OUD	Opioid Use Disorder
PKA	Protein Kinase A
QST	Quantitative Sensory Testing
SAMHSA	Substance Abuse and Mental Health Services Administration (U.S.)
SOAPP	Screener and Opioid Assessment for Patients with Pain
VAS	Visual Analogue Scale
VRS	Verbal Rating Scale
VTA	Ventral Tegmental Area
WHO	World Health Organization