SUD is considered to be a drug-induced disorder of neuroplasticity (Hyman, 2005; Impey, 2007; Jones & Bonci, 2005; Kalivas, 2005; Kalivas & O’Brien, 2008a; Kauer & Malenka, 2007; Koob & Le Moal, 2005; Lu, et al., 2006; McClung, et al., 2004; Moghaddam & Homayoun, 2008; Mulholland & Chandler, 2007; Volman, 2007). There is increasing evidence from the animal and molecular literature suggesting drug use modifies protein translation influencing neurons and neuroplasticity in circuits that parse reinforcement. Hundreds of miRNAs are expressed in the mature mammalian brain, and amongst many other functions, miRNAs are involved in the control of synapse development and neuronal plasticity (Banerjee, Neveu, & Kosik, 2009; Schratt et al., 2006; Siegel, Saba, & Schratt, 2011). Most human studies of the involvement of miRNAs in SUD have focused on cocaine use. These studies indicate widespread changes in dopaminergic, glutamatergic, and peptidergic neurotransmitter systems as well as proteins involved in the control of cytoskeletal organization and transcriptional regulation (Bali & Kenny, 2013; Lehrmann et al., 2003; Mains, Kiraly, Eipper-Mains, Ma, & Eipper, 2011).
