title: A possible role of opioid substances in depression.
mesh_terms: D003866:Depressive Disorder / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology*; D004723:Endorphins / Q000097:blood / Q000134:cerebrospinal fluid / Q000502:physiology*; D006801:Humans; D019964:Mood Disorders / Q000188:drug therapy; D009270:Naloxone / Q000627:therapeutic use; D009294:Narcotics / Q000627:therapeutic use
chemical_list: D004723:Endorphins; D009294:Narcotics; D009270:Naloxone