Thus, in contrast to the positive effects of short-termexposure to basal CRH levels, the peptide exposure undersevere stress, when the hormone level is increased, leads tothe loss of synapses for a longer period (Chen et al., 2012).Consistent with this, memory impairments are common inpeople with post-traumatic stress disorder (PTSD) (Brewinet al., 2007), and repeated injection of the selective CRHR1 antagonist prevents this cognitive impairment and the associated decrease in the excitability of hippocampal neurons ina mouse model of PTSD (Philbert et al., 2013). This evidence concerns the gene CRHR1 and post-traumatic stress disorder.