Phencyclidine (PCP), an NMDA antagonist with psychomimetic effects that resemble positive and negative symptoms of schizophrenia, produces opposite effects on Arc mRNA in juvenile and adult rats in the mPFC, orbitofrontal cortex and NAc shell, where it decreases expression in juveniles and increases it in adults when administered for 5 days (Thomsen et al., 2010). The gene discussed is ARC; the disease is schizophrenia.