Original ArticlesLow platelet-poor plasma concentrations of serotonin in patients with combat-related posttraumatic stress disorder
Introduction
Several studies have described the simultaneous activation of the noradrenergic, dopaminergic, and serotonergic mediated systems immediately following exposure to severe psychological trauma Charney et al 1993, Sutherland and Davidson 1994. This has been suggested to be an adaptive response necessary for survival; however, in cases of posttraumatic stress disorder (PTSD), it may become maladaptive and may lead to a chronic neurobiological dysfunction Charney et al 1993, Southwick et al 1994.
Although PTSD-related activation of the noradrenergic system has been well demonstrated, the mechanism of involvement of the other neurotransmitter systems (e.g., serotonergic and dopaminergic systems) that may be also important in the development and expression of the clinical symptoms of PTSD are less clear Yehuda et al 1992, Southwick et al 1993, Sutherland and Davidson 1994, Weizman et al 1996, Wang et al 1997.
The elevated urinary dopamine (DA), norepinephrine (NE), and epinephrine excretion observed in affected patients indicated that increased catecholaminergic activity is associated with PTSD (Yehuda et al 1992). In addition, the overlap of clinical symptoms of depression, anxiety disorders, and PTSD, together with the relative efficacy of selective serotonin reuptake inhibitors in all these disorders, suggests a possible serotonergic dysregulation in PTSD Nagy et al 1993, Sutherland and Davidson 1994, Weizman et al 1996.
The aim of the present study was to examine the involvement of the serotonergic and catecholaminergic systems in chronic combat-related PTSD (CR-PTSD).
Section snippets
Patients
The study group consisted of 17 male Israeli combat veterans with a primary diagnosis of CR-PTSD. Mean (±SD) age of the group was 33.1 ± 7.4 years, and mean (±SD) duration of PTSD symptoms was 7.8 ± 6.8 years. The diagnosis of PTSD was based on the DSM-III-R criteria and was established during military service; none of the subjects had previous psychiatric treatment prior to that evaluation. The patients were interviewed (by B.S.) according to the guidelines of the Structured Clinical Interview
Results
There was no significant difference between CR-PTSD patients and the healthy control subjects in age (t = 2.1, df = 25, p = .3). Scores on the PTSD scale (study group only) ranged from 22 to 40 points (mean ± SD, 31.9 ± 4.9), and the total IES score was 31.2 ± 3.8; there was no significant difference in the IES score between intrusive and avoidance symptoms (17.5 ± 1.9 and 13.6 ± 3.4, respectively; p = .4). The HDRS score was significantly higher in the CR-PTSD patients (18.7 ± 7.7) than in the
Discussion
Our results are in agreement with previous findings of increased 24-hour urinary catecholamine excretion (NE and DA) as well as the DA metabolite (HVA) in patients with CR-PTSD compared to healthy control subjects Yehuda et al 1992, Kosten et al 1987. Furthermore, the urinary NE and DA measures showed a significant intercorrelation in the PTSD group but not in the control subjects. The correlation between urinary DA and HVA in the PTSD patients did not reach statistical significance, though a
References (50)
- et al.
Paroxetine binding in the blood platelets of posttraumatic stress disorder patients
Life Sci
(1993) - et al.
Psychological stress increases serotonin release in the rat amygdala and prefrontal cortex assessed by in vivo microdialysis
Neurosci Lett
(1993) - et al.
Influence of dopamine agonists on plasma and brain levels of homovanillic acid
Life Sci
(1982) - et al.
Sustained urinary norepinephrine elevation in posttraumtic stress disorder
Psychoneuroendocrinology
(1987) - et al.
Effects of noxious tail pinch on the discharge rate of mesocortical and mesolimbic dopamine neuronsSelective activation of the mesocortical system
Brain Res
(1989) - et al.
Autonomic responses to stress in Vietnam veterans with posttraumatic stress disorder
Biol Psychiatry
(1990) - et al.
Prevention of learned helplessnessIn vivo correlation with cortical serotonin
Pharmacol Biochem Behav
(1992) - et al.
Twenty-four hour urinary cortisol and catecholamine excretion in combat-related posttraumatic stress disorder
Biol Psychiatry
(1990) - et al.
In vivo measurement of hypothalamic serotonin release by intracerebral microdialysisSignificant enhancement by immobilization stress in rats
Brain Res Bull
(1992) - et al.
Psychobiologic research in posttraumatic stress disorder
Psychiatr Clin North Am
(1994)