Given that CRH gene has a CRE motif in its promoter sequence, it might be proposed that FosB/ΔFosB accumulation in CRH neurons can mediate the morphine-induced changes in CRH levels, as reported for cocaine effects [42], especially in the CeA and the BNST, where, for the first time, we reported an enhancement in the number of CRH-positive neurons during morphine dependence. Here, FOSB is linked to substance dependence.