The serotonin 1A receptor (5-HT1A) and its associated transcriptional regulators, five prime repressor element under dual repression (Freud-1) and nuclear-deformed epidermal autoregulatory factor (NUDR/Deaf-1) have been previously found to be the repressors for 5-HT1A in the serotonergic raphe neurons, and are also altered in postmortem brains of individuals with major depressive disorder (MDD) and in rats exposed to chronic restraint stress.
When the data was combined across genders and analysed by age, the decrease in Freud-1 protein level was greater in the younger MDD subjects (48%, p=0.01) relative to age-matched controls as opposed to older depressed subjects.