1. ¹Mood and Anxiety Disorders Program, National Institute of Mental Health, Bethesda, MD, USA
2. ²Community Behavioral Health, Rockville, MD, USA
3. ³Mount Sinai School of Medicine, New York, NY, USA

Correspondence: Dr M Vythilingam, NIH NIMH/MAP, 15K North Drive, Room # 111, MSC 2670, Bethesda, MD 20892-2670, USA. Tel: 301 594 1798; Fax: 301 594 9959; E-mail: meena.vythi@nih.gov

Received 1 September 2004; Revised 15 April 2005; Accepted 16 June 2005; Published online 3 August 2005.

Abstract

Trace eyeblink conditioning is a hippocampal-dependent associative learning task that could help evaluate hippocampal function in Post-traumatic stress disorder (PTSD). Since preclinical research has demonstrated that trace eyeblink conditioning can be pharmacologically manipulated by glucocorticoids, this task may shed light on glucocorticoid sensitivity in PTSD. This study assessed baseline and hydrocortisone-mediated changes in trace eyeblink conditioning in patients with PTSD and in healthy controls. A total of 12 patients with PTSD and 12 age- and sex-matched healthy controls participated in a trace eyeblink test 6 h following intravenous administration of 30 mg of hydrocortisone. Spontaneous blink rates were similar between PTSD patients and healthy controls. There was no significant difference in the mean conditioned response between PTSD subjects and healthy controls under placebo conditions. Following hydrocortisone administration, only the PTSD patients demonstrated a significant reduction in conditioned response in contrast to healthy subjects who did not demonstrate any change. Patients with PTSD had increased glucocorticoid sensitivity in the focal brain regions mediating trace eyeblink conditioning.