Altered platelet peripheral-type benzodiazepine receptor in posttraumatic stress disorder

Peripheral-type benzodiazephine receptors (PEA) are involved in steroidogenesis and are sensitive to stress. Reduced platelet PBX density has been demonstrated in generalized anxiety disorder (GAD), but not in obsessive compulsive disorder (OCD). We extended this observation to another anxiety disorder, namely posttraumatic stress disorder (PTSD). Eighteen post-Persian Gulf War PTSD patients and 17 age- and sex-matched controls were included in the study. All subjects were evaluated using the Structured Clinical Interview for DSM-III-R-Patient Version. The severity of symptoms was assessed using the DSM-III-A scale for PTSD, the Impact of Event Scale, the Beck Depression Inventory, and the State-Trait Anxiety Inventory. [³H]PK 11195 was used to label platelet PBX. All psychological parameters (except trait anxiety) were higher in PTSD patients compared to controls. Decreased platelet PER density (-62%; p < .001) was observed in the PTSD patients compared to controls. The reduction in PBX observed in PTSD patients was in accordance with the findings in GAD patients, but differed from those obtained in OCD patients. It is possible that the receptoral down regulation is an adaptive response aimed at preventing chronic overproduction of glucocorticoids in hyperarousal states.