Stress hormone release with respect to acute heroin use was evaluated recently and a close association between reduced left amygdala responses, lower anxiety levels and lower concentrations of stress biomarkers, such as adrenocorticotropic hormone, serum cortisol and saliva cortisol, was identified after administration of heroin.49 Heroin users might ultimately adapt to the dampening of anxiety by continuously using heroin and might develop an unhealthy mechanism of managing increased anxiety, paired with structural changes in underlying brain connectivity. Here, POMC is linked to Anxiety.