Negative association of neuroticism with brain volume ratio in healthy humans

Background: Brain volume decreases with normal aging. We sought to determin e whether, in addition to age, individual differences in stress reactivity (i.e., neuroticism) would also predict reductions in brain volume. Methods: Brain volume ratios were calculated for a sample of 86 healthy vol unteers, based on segmented brain volumes taken from T-1-weighted magnetic resonance imaging and corrected for intracranial volume. Standardized self- reported measures of dispositional neuroticism were concurrently obtained b y administering the Revised NEO Personality Inventory. Results: After statistically controlling for age and sex, neuroticism showe d a significant negative association with the ratio of brain to the remaind er of the intracranial volume, but was not related to intracranial volume i tself. In particular, subfactors of neuroticism related to the chronic expe rience of arousing negative emotions were associated with reduced brain rat io. Conclusions: These results suggest that individual differences in stress re activity contribute to reductions in brain volume observed during adulthood . (C) 2001 Society of Biological Psychiatry.