CAMs	Cell adhesion molecules
CTCF	CCCTC-binding factor
DMP	Differentially methylated probe
EWAS	Epigenome-wide association study
GO	Gene ontology
GTEx	Genotype-Tissue Expression portal
GSA	Global Screening Array
HPA	Hypothalamic–Pituitary–Adrenal
KMSK	Kreek–McHugh–Schluger–Kellogg
KEGG	Kyoto Encyclopedia of Genes and Genomes
lncRNA	Long non-coding RNA
MMT	Methadone maintenance treatment
OUD	Opioid use disorder
PCA	Principal component analysis
QC	Quality control
DSM-IV	The Diagnostic and Statistical Manual of Mental Disorders, 4th Edition