Short-term stress or short-term use of hydrocortisone may impair memory, according to a study by UT Southwestern Medical Center psychiatrists. During stress, the body increases production of cortisol, which prevents inflammation. Extended exposure to cortisol, or the manufactured corticosteroid, hydrocortisone, is known to reduce the size of the brain’s hippocampus, which plays a critical role in memory. Prednisone and other medications of the same class as hydrocortisone are often used to reduce symptoms of allergies, asthma, or skin irritation. 

The study led by Dr. Sherwood Brown, Professor of Psychiatry at UT Southwestern, showed that cortisol or hydrocortisone exposure of just three days can reduce hippocampal size. This is the first report of structural changes in the hippocampus arising from brief corticosteroid exposure. The study, funded by a grant from the National Institutes of Health, appeared in the journal Neuropsychopharmacology.

When hydrocortisone use is stopped, the hippocampus appears to return to normal size within three weeks. As part of the test, the drug phenytoin was found to block hippocampal volume loss when taken with hydrocortisone. Phenytoin’s ability to block the effect suggests that the neurotransmitter glutamate may, at least in part, be responsible for the changes observed in the hippocampus.

Other study researchers included: Dr. Carol Tamminga, Chair of Psychiatry; Dr. Alyson Nakamura, Associate Professor of Psychiatry; Dr. Haekyung Jeon-Slaughter, Assistant Professor of Psychiatry; and Binu Thomas, senior research scientist.

Dr. Brown holds the Aradine S. Ard Chair in Brain Science. Dr. Tamminga holds the McKenzie Foundation Chair in Psychiatry I, the Lou and Ellen McGinley Distinguished Chair in Psychiatric Research, and the Communities Foundation of Texas [Inc.] Chair in Brain Science.