Mice in morphine withdrawal that received optogenetic inhibition of CeA PV + neurons exhibited ↓ anxiety and aversive behaviors and ↓ CRF mRNA levels. Mice spent ↓ time in the open arms of the EPM test, a ↓ preference for saccharin, and higher CPA scores. Activation of PV + neurons induced negative affective-like behaviors. The gene discussed is CRH; the disease is Anxiety.