Paroxetine binding in the blood platelets of post-traumatic stress disorder patients

Geraniol attenuates behavioral and neurochemical impairments by inhibitions of HPA-axis and oxido-inflammatory perturbations in mice exposed to post-traumatic stress disorder

Geraniol is an acyclic isoprenoid monoterpenoid analogue that has been shown to elicit neuroprotective functions, primarily through its ability to stimulate antioxidant and anti-inflammatory systems. An increase in inflammatory cytokines and oxidative stress exacerbate activation hypothalamic-pituitary-adrenal axis (HPA), leading to neurochemical dysfunction, which has important roles in the pathogenesis of post-traumatic disorder (PTSD), a mental health disorder characterized of post-trauma-induced intense fear. The aim of this study was to evaluate the anti-PTSD-like effects and underlying mechanisms of geraniol against single-prolonged-stress (SPS)-induced PTSD in mice. Following concomitant exposure to SPS (triple-paradigm traumatic events) and isolation for 7 days, mice (n = 9) were treated with geraniol (50 and 100 mg/kg, p.o.) or fluoxetine (10 mg/kg, p.o.) from days 8-21. Mice were assessed for behavioral changes. Neurochemical changes, inflammatory, oxido-nitrergic markers, adrenal weight, serum glucose and corticosterone concentrations were assayed. Geraniol inhibits SPS-induced anxiety- and depressive-like features as well as behavioral despair in the depression paradigms. SPS-induced locomotor and memory impairments were also abated by geraniol treatment similarly to fluoxetine. SPS-induced adrenal hypertrophy and increased blood glucose and corticosterone concentrations, were attenuated by the geraniol treatment. Elevated levels of TNF-α and IL-6, and malondialdehyde, nitrite, acetylcholinesterase enzyme were reduced by geraniol. Geraniol also increased glutathione, superoxide-dismutase, and catalase levels as well as dopamine, serotonin concentrations and GABAergic glutamic acid decarboxylase enzyme activity in the striatum, prefrontal cortex and hippocampus in the PTSD-mice relative to SPS control. In conclusion, geraniol attenuates behavioral impairments and neurochemical dysregulations by inhibitions of HPA-axis and oxido-inflammatory perturbations in mice exposed to PTSD.

Hypothalamus and Post-Traumatic Stress Disorder: A Review

Humans have lived in a dynamic environment fraught with potential dangers for thousands of years. While fear and stress were crucial for the survival of our ancestors, today, they are mostly considered harmful factors, threatening both our physical and mental health. Trauma is a highly stressful, often life-threatening event or a series of events, such as sexual assault, war, natural disasters, burns, and car accidents. Trauma can cause pathological metaplasticity, leading to long-lasting behavioral changes and impairing an individual's ability to cope with future challenges. If an individual is vulnerable, a tremendously traumatic event may result in post-traumatic stress disorder (PTSD). The hypothalamus is critical in initiating hormonal responses to stressful stimuli via the hypothalamic-pituitary-adrenal (HPA) axis. Linked to the prefrontal cortex and limbic structures, especially the amygdala and hippocampus, the hypothalamus acts as a central hub, integrating physiological aspects of the stress response. Consequently, the hypothalamic functions have been attributed to the pathophysiology of PTSD. However, apart from the well-known role of the HPA axis, the hypothalamus may also play different roles in the development of PTSD through other pathways, including the hypothalamic-pituitary-thyroid (HPT) and hypothalamic-pituitary-gonadal (HPG) axes, as well as by secreting growth hormone, prolactin, dopamine, and oxytocin. This review aims to summarize the current evidence regarding the neuroendocrine functions of the hypothalamus, which are correlated with the development of PTSD. A better understanding of the role of the hypothalamus in PTSD could help develop better treatments for this debilitating condition.

Brain Monoamine Dysfunction in Response to Predator Scent Stress Accompanies Stress-Susceptibility in Female Rats

Post-traumatic stress disorder (PTSD) is prevalent in women; however, preclinical research on PTSD has predominantly been conducted in male animals. Using a predator scent stress (PSS) rodent model of PTSD, we sought to determine if stress-susceptible female rats show altered monoamine concentrations in brain regions associated with PTSD: the medial prefrontal cortex (mPFC), nucleus accumbens (NAc), and dorsal (dHIPP) and ventral (vHIPP) hippocampus. Female Sprague-Dawley rats were exposed to a single, 10-min PSS exposure and tested for persistent anhedonia, fear, and anxiety-like behavior over four weeks. Rats were phenotyped as stress-Susceptible based on sucrose consumption in the sucrose preference task and time spent in the open arms of the elevated plus maze. Brain tissue was collected, and norepinephrine, dopamine, serotonin, and their metabolites were quantified using high-performance liquid chromatography. Stress-susceptibility in female rats was associated with increased dopamine and serotonin turnover in the mPFC. Susceptibility was also associated with elevated dopamine turnover in the NAc and increased norepinephrine in the vHIPP. Our findings suggest that stress-susceptibility after a single stress exposure is associated with long-term effects on monoamine function in female rats. These data suggest interventions that decrease monoamine turnover, such as MAOIs, may be effective in the treatment of PTSD in women.

The Anterior Piriform Cortex and Predator Odor Responses: Modulation by Inhibitory Circuits

Rodents acquire more information from the sense of smell than humans because they have a nearly fourfold greater variety of olfactory receptors. They use olfactory information not only for obtaining food, but also for detecting environmental dangers. Predator-derived odor compounds provoke instinctive fear and stress reactions in animals. Inbred lines of experimental animals react in an innate stereotypical manner to predators even without prior exposure. Predator odors have also been used in models of various neuropsychiatric disorders, including post-traumatic stress disorder following a life-threatening event. Although several brain regions have been reported to be involved in predator odor-induced stress responses, in this mini review, we focus on the functional role of inhibitory neural circuits, especially in the anterior piriform cortex (APC). We also discuss the changes in these neural circuits following innate reactions to odor exposure. Furthermore, based on the three types of modulation of the stress response observed by our group using the synthetic fox odorant 2,5-dihydro-2,4,5-trimethylthiazoline, we describe how the APC interacts with other brain regions to regulate the stress response. Finally, we discuss the potential therapeutic application of odors in the treatment of stress-related disorders. A clearer understanding of the odor–stress response is needed to allow targeted modulation of the monoaminergic system and of the intracerebral inhibitory networks. It would be improved the quality of life of those who have stress-related conditions.

Early adolescent stress-induced changes in prefrontal cortex miRNA-135a and hippocampal miRNA-16 in male rats

Early-life stress increases susceptibility to post-traumatic stress disorders (PTSD), in which the dysfunction of 5-hydroxytryptamine plays an important role. miRNA-135a in the prefrontal cortex (PFC) and miRNA-16 in the hippocampus (HIP) are closely related to the 5-HT neurotransmitter system. Here, we investigated behavior, miRNA-135a in the PFC, miRNA-16 in the HIP, and 5-HT1AR expression in both brain regions in adolescent and adult rats that were exposed to inescapable stress during their adolescence. Paroxetine hydrochloride and corticotropin-releasing factor antagonist (CP-154,526) were used as intervening measures. Our study demonstrated that early adolescent stress induced anxiety-like behaviors and spatial memory damage, a reduction in miRNA-135a expression was associated with increased 5-HT1AR expression in PFC, and increased miRNA-16 expression in the HIP of stressed rats. Drug treatments alleviated behaviors and reversed the miRNA-135a, miRNA-16, and 5-HT1AR expression in stressed rats.

Epigenetic programming of the neuroendocrine stress response by adult life stress

The hypothalamic-pituitary-adrenal (HPA) axis is critically involved in the neuroendocrine regulation of stress adaptation, and the restoration of homeostasis following stress exposure. Dysregulation of this axis is associated with stress-related pathologies like major depressive disorder, post-traumatic stress disorder, panic disorder and chronic anxiety. It has long been understood that stress during early life can have a significant lasting influence on the development of the neuroendocrine system and its neural regulators, partially by modifying epigenetic regulation of gene expression, with implications for health and well-being in later life. Evidence is accumulating that epigenetic plasticity also extends to adulthood, proposing it as a mechanism by which psychological trauma later in life can long-lastingly affect HPA axis function, brain plasticity, neuronal function and behavioural adaptation to neuropsychological stress. Further corroborating this claim is the phenomenon that these epigenetic changes correlate with the behavioural consequences of trauma exposure. Thereby, epigenetic modifications provide a putative molecular mechanism by which the behavioural phenotype and transcriptional/translational potential of genes involved in HPA axis regulation can change drastically in response to environmental challenges, and appear an important target for treatment of stress-related disorders. However, improved insight is required to increase their therapeutic (drug) potential. Here, we provide an overview of the growing body of literature describing the epigenetic modulation of the (primarily neuroendocrine) stress response as a consequence of adult life stress and interpret the implications for, and the challenges involved in applying this knowledge to, the identification and treatment of stress-related psychiatric disorders.

Intensity-Dependent Auditory Evoked Potential Defines Subgroups of Patients with PTSD: A Multimodality Imaging Study

Post Traumatic Stress Disorder (PTSD) is a complex and heterogeneous psychiatric disorder. Patients with chronic PTSD present with significant psychiatric co-morbidities. Current treatment guidelines recommend the use of selective serotonin reuptake inhibitors in PTSD patients, but only 50–60% of these patients respond favorably. To improve the response rate, understanding the underlying pathophysiology is necessary. Serotonergic transmission has been implicated in PTSD and the intensity-dependent auditory evoked potential (IDAEP) is presumed to reflect central serotonergic activity, thereby providing an opportunity to more precisely characterize PTSD patient populations and possibly predict response to treatment. We studied nineteen patients diagnosed with PTSD, matched for age and medications. Based on the stimulus intensity relationship, the patients were divided into two groups: augmenters and reducers. These groups were further evaluated using resting state quantitative EEG and HMPAO-based SPECT brain perfusion acquired simultaneously. The imaging data were correlated with behavioral measures characterizing symptoms of PTSD and measurements of mood state. The augmenters differed from the reducers in the resting state quantitative EEG and SPECT perfusion measures. The differences were primarily localized to the right hemisphere. There were significant differences in measures of PTSD symptoms, but not in overall measures of depression. Item analysis of depression measures showed a significant difference between the augmenters and the reducers in reported sleep difficulties, which correlated with the reported anxiety measures. Objective separation of patients into subgroups based on the IDAEP contributes to the understanding of PTSD biological substrate and can potentially lead to more effective treatment strategies.

Diagnostic Biomarkers for Posttraumatic Stress Disorder: Promising Horizons from Translational Neuroscience Research

Posttraumatic stress disorder (PTSD) is a heterogeneous disorder that affects individuals exposed to trauma (e.g., combat, interpersonal violence, and natural disasters). Although its diagnostic features have been recently reclassified with the emergence of the Diagnostic and Statistical Manual for Mental Disorders, Fifth Edition, the disorder remains characterized by hyperarousal, intrusive reminders of the trauma, avoidance of trauma-related cues, and negative cognition and mood. This heterogeneity indicates the presence of multiple neurobiological mechanisms underlying the etiology and maintenance of PTSD. Translational research spanning the past few decades has revealed several potential avenues for the identification of diagnostic biomarkers for PTSD. These include, but are not limited to, monoaminergic transmitter systems, the hypothalamic-pituitary-adrenal axis, metabolic hormonal pathways, inflammatory mechanisms, psychophysiological reactivity, and neural circuits. The current review provides an update to the literature with regard to the most promising putative PTSD biomarkers, with specific emphasis on the interaction between neurobiological influences on disease risk and symptom progression. Such biomarkers will most likely be identified by multi-dimensional models derived from comprehensive descriptions of molecular, neurobiological, behavioral, and clinical phenotypes.

Differential effects of sertraline in a predator exposure animal model of post-traumatic stress disorder

Serotonin (5-HT), norepinephrine (NE), and other neurotransmitters are modulated in post-traumatic stress disorder (PTSD). In addition, pro-inflammatory cytokines (PIC) are elevated during the progression of the disorder. Currently, the only approved pharmacologic treatments for PTSD are the selective-serotonin reuptake inhibitors (SSRI) sertraline and paroxetine, but their efficacy in treating PTSD is marginal at best. In combat-related PTSD, SSRIs are of limited effectiveness. Thus, this study sought to analyze the effects of the SSRI sertraline on inflammation and neurotransmitter modulation via a predator exposure/psychosocial stress animal model of PTSD. We hypothesized that sertraline would diminish inflammatory components and increase 5-HT but might also affect levels of other neurotransmitters, particularly NE. PTSD-like effects were induced in male Sprague-Dawley rats (n = 6/group × 4 groups). The rats were secured in Plexiglas cylinders and placed in a cage with a cat for 1 h on days 1 and 11 of a 31-day stress regimen. PTSD rats were also subjected to psychosocial stress via daily cage cohort changes. At the conclusion of the stress regimen, treatment group animals were injected intraperitoneally (i.p.) with sertraline HCl at 10 mg/kg for 7 consecutive days, while controls received i.p. vehicle. The animals were subsequently sacrificed on day 8. Sertraline attenuated inflammatory markers and normalized 5-HT levels in the central nervous system (CNS). In contrast, sertraline produced elevations in NE in the CNS and systemic circulation of SSRI treated PTSD and control groups. This increase in NE suggests SSRIs produce a heightened noradrenergic response, which might elevate anxiety in a clinical setting.

The unfolded protein response is triggered in rat neurons of the dorsal raphe nucleus after single-prolonged stress

The dorsal raphe nucleus (DRN) has been suggested playing an important role in the pathophysiology of post-traumatic stress disorder (PTSD), however the underlying cellular mechanisms are not fully understood. The endoplasmic reticulum (ER) is a critical organelle for synthesis of membrane and secretory proteins, and perturbations in ER lead to the unfolded protein response (UPR). In the present experiment, we hypothesized UPR may be associated with the PTSD, and there is an induction of UPR in the DRN neurons of the PTSD-like rats. We first observed the morphological changes of ER in the DRN neurons of the rats exposed to single-prolonged stress (SPS), a model of PTSD, and then we also detected the expression of ER chaperones glucose regulated protein 78 (GRP78) and glucose regulated protein (GRP94) which are two key sensors and mediators of the UPR and are considered an ER stress-specific inducible proteins using methods of western blot and immunohistochemical analysis. Our results demonstrated there were abnormal expansion of ER and up-regulation expression of GRP78 and GRP94 after SPS, which indicated that the UPR was triggered in the DRN neurons of the PTSD-like rats. These results are consistent with our speculation that UPR may be associated with the PTSD, and suggest us the UPR may be a new critical cellular mechanisms of PTSD.

Predator exposure/psychosocial stress animal model of post-traumatic stress disorder modulates neurotransmitters in the rat hippocampus and prefrontal cortex

Post-Traumatic Stress Disorder (PTSD) can develop in response to a traumatic event involving a threat to life. To date, no diagnostic biomarkers have been identified for PTSD. Recent research points toward physiological abnormalities in the hypothalamic-pituitary-adrenal (HPA) axis, sympathoadrenal medullary and immune system that may be implicated in the disorder. The modulation of neurotransmitters is another possible mechanism, but their role in the progression of PTSD is poorly understood. Low serotonin (5-HT) may be a factor, but it may not be the only neurotransmitter affected as modulation affects levels of other neurotransmitters. In this study, we hypothesized the predator exposure/psychosocial stress rodent model of PTSD may alter levels of 5-HT and other neurotransmitters in the rat hippocampus and prefrontal cortex (PFC). Male Sprague-Dawley rats were used in this experiment. We induced PTSD via a predator exposure/psychosocial stress model, whereby rats were placed in a cage with a cat for 1 hour on days 1 and 11 of the 31-day experiment. Rats also received psychosocial stress via daily cage cohort changes. On day 32, the rats were sacrificed and the brains dissected to remove the hippocampus and PFC. Norepinephrine (NE), 5-Hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), dopamine (DA), and 3,4-Dihydroxyphenylacetic acid (DOPAC), and 5-HT levels in the hippocampus and PFC were measured with high-performance liquid chromatography (HPLC). In the hippocampus, 5-HT and HVA were lower, while NE and DOPAC were higher, in the PTSD group vs. controls. In the PFC, only 5-HT was lower, while NE, DA, and DOPAC were higher, in the PTSD group vs. controls. The rate limiting enzymes tyrosine hydroxylase and tryptophan hydroxylase were also examined and confirmed our findings. These results demonstrate that the predator exposure/psychosocial stress model of PTSD produces neurotransmitter changes similar to those seen in human patients and may cause a heightened noradrenergic response.

Neuro-psychopharmacogenetics and Neurological Antecedents of Posttraumatic Stress Disorder: Unlocking the Mysteries of Resilience and Vulnerability

BACKGROUND AND HYPOTHESIS

Although the biological underpinnings of immediate and protracted trauma-related responses are extremely complex, 40 years of research on humans and other mammals have demonstrated that trauma (particularly trauma early in the life cycle) has long-term effects on neurochemical responses to stressful events. These effects include the magnitude of the catecholamine response and the duration and extent of the cortisol response. In addition, a number of other biological systems are involved, including mesolimbic brain structures and various neurotransmitters. An understanding of the many genetic and environmental interactions contributing to stress-related responses will provide a diagnostic and treatment map, which will illuminate the vulnerability and resilience of individuals to Posttraumatic Stress Disorder (PTSD).

PROPOSAL AND CONCLUSIONS

We propose that successful treatment of PTSD will involve preliminary genetic testing for specific polymorphisms. Early detection is especially important, because early treatment can improve outcome. When genetic testing reveals deficiencies, vulnerable individuals can be recommended for treatment with "body friendly" pharmacologic substances and/or nutrients. Results of our research suggest the following genes should be tested: serotoninergic, dopaminergic (DRD2, DAT, DBH), glucocorticoid, GABAergic (GABRB), apolipoprotein systems (APOE2), brain-derived neurotrophic factor, Monamine B, CNR1, Myo6, CRF-1 and CRF-2 receptors, and neuropeptide Y (NPY). Treatment in part should be developed that would up-regulate the expression of these genes to bring about a feeling of well being as well as a reduction in the frequency and intensity of the symptoms of PTSD.

Extended-release formulation of venlafaxine in the treatment of post-traumatic stress disorder

There is abundant evidence for abnormalities of both norepinephrine and serotonin neurotransmitter systems in post-traumatic stress disorder (PTSD). Venlafaxine extended-release formulation (venlafaxine XR) is a serotonin and norepinephrine re-uptake inhibitor with antidepressant and anxiolytic properties relevant to the pathophysiology of PTSD. Venlafaxine XR is currently approved for the treatment of panic disorder, generalized anxiety disorder and social anxiety disorder, as well as major depression in adults, based on a number of randomized, double blind, placebo-controlled clinical trials. Limited data also demonstrate that venlafaxine XR maintains a therapeutic response for more than 6 months in these anxiety disorders. Venlafaxine XR has demonstrated short- and long-term efficacy for the treatment of PTSD in two recent randomized, double-blind, placebo-controlled clinical trials, although it has not been extensively studied for PTSD, compared with other anxiety disorders. This review focuses on the potential role of venlafaxine XR in the treatment of PTSD, based on currently available evidence.

Models of PTSD and traumatic stress: the importance of research "from bedside to bench to bedside"

The epidemiology and psychology of PTSD noted above is not often considered in neurobiological models of PTSD. Neurobiological models tend to focus on symptoms. This is an important perspective but it does not capture the brains total response to traumatic events. Similarly, neurobiologists have rarely used the extensive knowledge of animal behavioral responses to stress as a means to define the human stress phenomenology, looking for the human equivalent (rather than the other way around). The development of animal models for PTSD and other traumatic stress-related brain changes is an important part of advancing our neurobiological understanding of the disease process as well as recovery, resilience, and possible therapeutic targets. Animal models should address symptoms but also other aspects of PTSD that are seen in clinical care including the waxing and waning of symptoms, Understanding "forgetting", toxic exposure, failure to recover and how the neural systems fail rather than function are important perspectives on developing animal models. The cognitive process of identification is another important animal model to develop. Using these perspectives recent work has shown new avenues for understanding the trauma response in animal models and human brain tissue of individuals with PTSD. The 5-HT2A receptor and p11 protein and associated regulators are avenues of new investigation that warrant study and consideration in models of PTSD.

Alterations in stress reactivity after long-term treatment with paroxetine in women with posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is typically accompanied by both acute and chronic alterations in the stress response. These alterations have mostly been described in individuals under baseline conditions, but studies have also used a challenge model to assess the role of the hypothalamic-pituitary-adrenal (HPA) axis in the stress response. The purpose of this article was to assess the effect of long-term treatment with the selective reuptake inhibitor (SSRI), paroxetine, on stress reactivity in patients with PTSD. We assessed diurnal salivary cortisol and urinary cortisol as well as cortisol, heart rate, and behavioral responses to a standardized cognitive stress challenge, in 13 female patients with chronic PTSD before and after 12 months of paroxetine treatment. Treatment resulted in a significant decrease in PTSD symptoms. Twenty-four-hour urinary cortisol was lower compared to base line after successful treatment. Treatment resulted in a decrease of salivary cortisol levels on all time points on a diurnal curve. Despite similar stress perception, cortisol response to the cognitive stress challenge resulted in a 26.5% relative decrease in stress-induced salivary cortisol with treatment. These results suggest that successful treatment with SSRI in chronic PTSD is associated with a trend for a decrease in baseline diurnal cortisol and with reduced cortisol reactivity to stress.

Adaptive and maladaptive psychobiological responses to severe psychological stress: implications for the discovery of novel pharmacotherapy

Post-traumatic stress disorder (PTSD) is one of the few DSM-IV diagnoses contingent upon a psychosocial stressor. In this context, there is an urgent need to acquire a better understanding of both the adaptive and maladaptive psychobiological responses to traumatic stress. Preclinical investigators have utilized a variety of animal models to identify the behavioral and neurobiological features of the organism's response to stress. However, given the complexity of the healthy and pathological human response to physiological and psychological stress, the extent to which the animal data is immediately transferable to human remains to be fully determined. This review draws upon preclinical and clinical literature to examine the transformation of an adaptive human stress response into a maladaptive and debilitating mental disorder. An integrative psychobiological model for PTSD is presented, linking psychological processes and behavioral patterns with current findings in neurocircuitry, neurochemistry and psychophysiology. The implications of this model for the discovery of novel pharmacological approaches to the treatment of severe psychological distress are discussed.

Single photon emission computed tomography in posttraumatic stress disorder before and after treatment with a selective serotonin reuptake inhibitor

BACKGROUND

Posttraumatic stress disorder (PTSD) is recognized as a disorder mediated by specific neurobiological circuits. Functional imaging studies using script-driven trauma imagery and pharmacological challenges have documented altered cerebral function (activation and deactivation) in several brain regions, including the amygdala, hippocampus, prefrontal cortex and anterior cingulate. However, the neural substrates of PTSD remain poorly understood and the effect of selective serotonin reuptake inhibition on regional cerebral activity is deserving of further investigation.

METHODS

Eleven adult patients (seven men, four women) (mean age+S.D.=33.6+/-9.2 years) with a DSM-IV diagnosis of PTSD, as determined by the Structured Clinical Interview for DSM-IV (SCID-I) and the Clinician-Administered PTSD Scale (CAPS), underwent single photon emission computed tomography (SPECT) with Tc-99m HMPAO pre- and post-8 weeks of treatment with the selective serotonin reuptake inhibitor, citalopram. Symptoms were assessed at baseline and at 2-week intervals with the Clinician-Administered PTSD Scale (CAPS), Montgomery-Asberg Depression Rating Scale (MADRS), and the Clinical Global Impression Scale (CGI). Image analysis of baseline and post-treatment scans was performed using Statistical Parametric Mapping (SPM).

RESULTS

Treatment with citalopram resulted in significant deactivation in the left medial temporal cortex irrespective of clinical response. On covariate analysis, a significant correlation between CAPS score reduction and activation in the left paracingulate region (medial prefrontal cortex) was observed post-treatment. No significant pre-treatment differences were observed between responders and non-responders in anterior cingulate perfusion.

CONCLUSIONS

These preliminary findings are consistent with clinical data indicating temporal and prefrontal cortical dysfunction in PTSD and preclinical data demonstrating serotonergic innervation of these regions. However, further studies, in particular in vivo receptor imaging studies, are needed to confirm whether these regional abnormalities correlate with clinical features and treatment response.

Glucocorticoid-regulated human serotonin transporter (5-HTT) expression is modulated by the 5-HTT gene-promotor-linked polymorphic region

Mood, emotion and cognition are modulated by serotonergic neurotransmission, while the physiological function of serotonergic synapses depends on serotonin reuptake, which is mediated by the serotonin transporter (5-HTT). Allelic variation of 5-HTT expression in humans is caused by a functional gene-promoter polymorphism with two predominant variant alleles, which are associated with variations in anxiety measures as previously reported. Here we report that administration of dexamethasone, a potent glucocorticosteroid hormone, results in an increase in 5-HTT expression in immortalized human B-lymphoblastoid cells, which express the human 5-HTT. Functional reporter gene assays as well as 5-HT uptake and inhibitor binding measures revealed a genotype-dependent dose-response to glucocorticosteroid administration, which was antagonized by RU 38486, a non-specific glucocorticosteroid hormone antagonist. The allele-specific differences after administration of dexamethasone depended on the repetitive GC-rich sequence located approximately 1.4 kb upstream of the 5-HTT gene transcription site because of absence of a significant steroid effect after transfecting a deletional mutant reporter gene construct, which lacks this repetitive promoter sequence. Our findings may contribute to explain the vulnerability to stress-related disorders in susceptible individuals, in whom further clinical studies should follow up on these in vitro findings.

Platelet 5-HT concentration and comorbid depression in war veterans with and without posttraumatic stress disorder

BACKGROUND

The serotonergic system is implicated in the pathophysiology of posttraumatic stress disorder (PTSD) and depression. The present study focused on platelet serotonin (5-HT) concentration and symptoms of comorbid depression in war veterans with or without PTSD.

METHODS

PTSD and depression were evaluated using Clinician Administered PTSD Scale, Davidson Trauma Scale, Montgomery-Asberg Depression Rating Scale and Hamilton Anxiety Scale. Sixty-five male drug-free war veterans (48 with PTSD and 17 without PTSD) and 65 age- and sex-matched healthy controls were studied.

RESULTS

Comorbid depression occurred in 54 and 31% of war veterans with PTSD and without PTSD, respectively. Platelet 5-HT concentration was similar in the groups of depressed and nondepressed war veterans with or without PTSD and healthy controls. Platelet 5-HT concentration was found to differ between war veterans with various degrees of appetite loss. A positive correlation was observed between platelet 5-HT concentration and severity of appetite loss in veterans with PTSD. There was no relationship between platelet 5-HT concentration and severity of other symptoms of PTSD or depression.

LIMITATIONS

War veterans included in the study were outpatients.

CONCLUSIONS

War veterans with PTSD had a high incidence of comorbid depression, that was not related to platelet 5-HT concentration. The marked relationship between platelet 5-HT concentration and severity of appetite loss, suggested that 5-HT system is involved in the regulation of appetite, at least in depressed war veterans with PTSD.

Biologic findings of post-traumatic stress disorder and child maltreatment

Child maltreatment is a serious problem in US society, affecting approximately three million children. Children and adolescents exposed to child abuse and neglect experience high rates of post-traumatic stress disorder (PTSD). In addition, they are at risk for comorbid mental illness. Biologic stress systems affected in trauma and in PTSD are complex. Findings in cognitive testing, neuroimaging, and affected pathways shed light on the consequences of child maltreatment. What is known about treatment and outcomes for children with history of maltreatment and maltreatment-related PTSD indicates the need for prevention, intervention, and treatment of children exposed to abuse and neglect. The following is a brief review of the most recent neurobiologic findings in child maltreatment and related PTSD.

Platelet serotonergic markers in posttraumatic stress disorder

The neurobiological basis of posttraumatic stress disorder (PTSD) is believed to involve alterations in different neurotransmitter systems, and recent studies elucidated the role of serotonin (5-hydroxytryptamine, 5-HT) in PTSD. The data on the role of 5-HT have been obtained using blood platelets as a peripheral model for central serotonergic neurons. The reports suggested that platelet 5-HT concentration and monoamine oxidase (MAO) activity might serve as biological, even trait, markers for particular mental disturbances. Since the data on the peripheral serotonergic markers in PTSD subjects are controversial, the aim of the study was to determine platelet 5-HT concentration and platelet MAO activity in war veterans with PTSD, war veterans who did not develop PTSD, and in war veterans who were prisoners of war and developed PTSD. Platelet 5-HT concentration and MAO activity did not differ significantly between war veterans with or without PTSD, and prisoners of war with PTSD. Clinician-Administered PTSD Scale (CAPS) scores did not differ between war veterans with PTSD and prisoners of war, but Montgomery-Asberg Depression Rating Scale (MADRS) scores were significantly higher in prisoners of war who developed PTSD than in war veterans with PTSD. There was no significant correlation between platelet 5-HT concentration or platelet MAO activity and CAPS or MADRS scores within these groups. Platelet 5-HT concentration was slightly higher and platelet MAO activity slightly lower in prisoners of war with PTSD, than in all other groups. These findings suggest that platelet 5-HT concentration and platelet MAO activity are not altered in three drug-free groups--war veterans who did or did not develop PTSD, or in prisoners of war with PTSD--and that these platelet serotonergic markers are not associated with symptoms of PTSD or comorbid depression.

Post-traumatic stress disorder: a review of psychobiology and pharmacotherapy

OBJECTIVE

To review the literature on the psychobiology and pharmacotherapy of PTSD.

METHODS

Relevant studies were identified by literature searches (Pub-med, Web of Science) and through reference lists. The search was ended by May 2001.

RESULTS

There is evidence of involvement of opioid, glutamatergic, GABAergic, noradrenergic, serotonergic and neuroendocrine pathways in the pathophysiology of PTSD. Medications shown to be effective in double-blind placebo-controlled trials includes selective serotonin reuptake inhibitors, reversible and irreversible MAO-inhibitors, tricyclic antidepressants and the anticonvulsant lamotrigine. Still more agents appear promising in open-label trials.

CONCLUSION

The complexity of the psychobiology is reflected by the difficulties in treating the disorder. According to the present knowledge, suggestions for drug treatment of PTSD are made.

Posttraumatic stress disorder: diagnosis and epidemiology, comorbidity and social consequences, biology and treatment

Epidemiological studies clearly indicate that posttraumatic stress disorder (PTSD) is becoming a major health concern worldwide even if still poorly recognized and not well treated. PTSD commonly co-occurs with other psychiatric disorders, and several symptoms overlap with major depressive disorders, anxiety disorders and substance abuse; this may contribute to diagnostic confusion and underdiagnosis. This anxiety disorder provokes significant occupational, psychiatric, medical and psychosocial disability, and its consequences are enormously costly, not only to the survivors and their families, but also to the health care system and society. Work impairment associated with PTSD is very similar to the amount of work impairment associated with major depression. The pathophysiology of PTSD is multifactorial and involves dysregulation of the serotonergic as well as the noradrenergic system. A rational therapeutic approach should normalize the specific psychobiological alterations associated with PTSD. This can be achieved through the use of antidepressant drugs, mainly of those that potentiate serotonergic mechanisms. Recent double-blind placebo-controlled studies report the efficacy of selective serotonin reuptake inhibitors. Several cognitive-behavioral and psychosocial treatments have also been reported to be efficacious and could be considered when treating PTSD patients.

Serotonergic markers and lowered plasma branched-chain-amino acid concentrations in fibromyalgia

The aims of the present study were to examine serotonergic markers, i.e. [3H]paroxetine binding characteristics and the availability of plasma tryptophan, the precursor of serotonin (5-HT), and the plasma concentrations of the branched chain amino acids (BCAAs), valine, leucine and isoleucine, in fibromyalgia. The [3H]paroxetine binding characteristics, B(max) and K(d) values, and tryptophan and the competing amino acids (CAA), known to compete for the same cerebral uptake mechanism (i.e. valine, leucine, isoleucine, phenylalanine and tyrosine), were determined in fibromyalgia patients and normal controls. There were no significant differences in the [3H]paroxetine binding characteristics (B(max) and K(d)) between fibromyalgia and control subjects. There were no significant differences in plasma tryptophan or the tryptophan/CAA ratio between fibromyalgia patients and normal controls. In the fibromyalgia patients, there were no significant correlations between [3H]paroxetine binding characteristics or the availability of tryptophan and myalgic or depressive symptoms. Patients with fibromyalgia had significantly lower plasma concentrations of the three BCAAs (valine, leucine and isoleucine) and phenylalanine than normal controls. It is hypothesized that the relative deficiency in the BCAAs may play a role in the pathophysiology of fibromyalgia, since the BCAAs supply energy to the muscle and regulate protein synthesis in the muscles. A supplemental trial with BCAAs in fibromyalgia appears to be justified.

Selective serotonin reuptake inhibitors in post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a complex psychiatric condition, which can be triggered by a variety of traumatic events. Lifetime prevalence rates range from 1.3% to 10.4%, with women twice as likely as men to be affected. The clinical management of this condition is complex, since PTSD is associated with high rates of comorbid psychiatric disorders, particularly major depression, other anxiety and panic disorders, substance abuse and antisocial behaviour. Broadly, there are two main approaches to treatment: pharmacotherapy and cognitive or behavioural therapy. This paper reviews available pharmacological approaches for the treatment of PTSD and comorbid disorders. Although the optimal pharmacological approach has yet to be established, there is increasing evidence to support the use of antidepressants, and particularly selective serotonin reuptake inhibitors (SSRIs), as first-line therapy. In addition to alleviating the core symptoms of PTSD, some SSRIs are also effective for the treatment of common comorbidities, such as depression, panic disorder and social anxiety disorder; a fact which would appear to have important implications for patient management.

Posttraumatic stress disorder and platelet serotonin measures

The role of serotonin (5HT) in the pathophysiology of posttraumatic stress disorder (PTSD) has been suggested by the overlap in clinical symptoms between PTSD and psychiatric conditions in which a serotonin dysfunction is implicated, as well as by the therapeutic efficiency of 5HT-related drugs (antidepressants, selective serotonin reuptake inhibitors and monoamine oxidase inhibitors) in alleviating symptoms in PTSD. In the present study, the blood platelet, which has been proposed as a peripheral model for the central serotonergic neurons, has been used to search for alterations in 5HT mechanisms in PTSD. Platelet serotonin level and kinetics of serotonin transporter and monoamine oxidase (MAO-B) were assessed in 63 combat-related PTSD patients and 43 sex and age-matched control subjects. A significant reduction in maximal velocity of platelet MAO-B (approx. 30%), with no changes in the enzyme affinity was observed in our patient sample. Conversely, no alterations in kinetic parameters (V(max), K(m)) of platelet serotonin transporter, as well as in platelet 5HT level, were found in the PTSD group.

Decreased platelet 3H-paroxetine binding in untreated panic disorder patients

Different findings support the involvement of the serotonin (5-HT) system in panic disorder. The presence of the 5-HT transporter in blood platelets similar to that in presynaptic serotonergic neurons, permits the investigation of this structure in periphery. We therefore evaluated the binding of 3H-paroxetine, a selective 5-HT reuptake inhibitor which is considered the ligand of choice for labelling the 5-HT transporter, in platelets of 20 drug-free patients with panic disorder. The same measurement was repeated after one year's treatment with different drugs. The results showed patients to have a lower number of 3H-paroxetine sites than a group of age- and sex-matched controls, thus suggesting the involvement of the 5-HT transporter in panic disorder. This abnormality reverted after one year of treatment with specific drugs that provoked the symptom remission in all cases, which would suggest a link with the clinical improvement.

Elevated serum interleukin-6 (IL-6) and IL-6 receptor concentrations in posttraumatic stress disorder following accidental man-made traumatic events

BACKGROUND

Recently, it has been reported that serum interleukin-1 beta (IL-1 beta), but not soluble IL-2 receptor (sIL-2R), concentrations were significantly higher in patients with posttraumatic stress disorder (PTSD) than in normal volunteers, and that psychological stress in humans is associated with increased secretion of proinflammatory cytokines, such as IL-6.

METHODS

The aim of the present study was to examine the inflammatory response system in patients with PTSD through measurements of serum IL-6, sIL-6R, sgp130 (the IL-6 signal transducing protein), sIL-1R antagonist (sIL-1RA; an endogenous IL-1 receptor antagonist), CC16 (an endogenous anticytokine), and sCD8 (the T suppressor-cytotoxic antigen).

RESULTS

Serum IL-6 and sIL-6R, but not sgp130, sIL-RA, CC16, or sCD8, concentrations were significantly higher in PTSD patients than in normal volunteers. Serum sIL-6R concentrations were significantly higher in PTSD patients with concurrent major depression than in PTSD patients without major depression and normal volunteers. There were no significant relationships between serum IL-6 or sIL-6R and severity measures of PTSD.

CONCLUSIONS

The results suggest that PTSD is associated with increased IL-6 signaling. It is hypothesized that stress-induced secretion of proinflammatory cytokines is involved in the catecholaminergic modulation of anxiety reactions.

Low platelet-poor plasma concentrations of serotonin in patients with combat-related posttraumatic stress disorder

BACKGROUND

Combat-related posttraumatic stress disorder (CR-PTSD) is associated with a dysregulation of various neurotransmitter systems.

METHODS

We assessed levels of platelet-poor plasma (PPP) norepinephrine (NE), and serotonin (5-HT), and 24-hour urinary excretion of NE, dopamine (DA), and homovanillic acid (HVA) in 17 male outpatients with untreated chronic CR-PTSD (age, 33.1 +/- 7.4 years) and 10 normal control subjects (age, 35.8 +/- 2.7 years).

RESULTS

Compared with the control subjects, the PTSD patients showed significantly lower PPP 5-HT levels, elevated PPP NE levels, and significantly higher mean 24-hour urinary excretion of all three catecholamines (NE, DA, and HVA). The 24-hour urinary HVA values of the CR-PTSD patients correlated significantly and positively with the total Impact of Event Scale scores and the avoidance symptoms cluster scores, and the PPP 5-HT levels correlated negatively with the Hamilton Anxiety Rating Scale scores. The PPP NE/5-HT ratio was significantly higher in the study group than in the control subjects.

CONCLUSIONS

We believe this combined enhanced noradrenergic activity and diminished 5-HT activity may be relevant to the neurobiology of CR-PTSD.

D-fenfluramine challenge in posttraumatic stress disorder

BACKGROUND

Much progress has been made in understanding the role of catecholamines in the pathophysiology of posttraumatic stress disorder (PTSD). Recent research has broadened the scope of neuroregulation of PTSD to include serotonin.

METHODS

We used the serotonin-releasing agent and reuptake inhibitor, d-fenfluramine, to assess the integrity of the serotonin-mediated prolactin release in 8 men with combat-induced PTSD and 8 healthy men.

RESULTS

The veterans with PTSD had a significantly lower prolactin response to d-fenfluramine as compared to healthy control subjects. The prolactin response to d-fenfluramine was inversely correlated with the patient's level of PTSD symptomatology and measures of aggression.

CONCLUSIONS

This study demonstrates a central serotonin dysfunction, as reflected in a lower prolactin response to d-fenfluramine, in patients with PTSD.

Platelet paroxetine binding in post-traumatic stress disorder

Sixty-two subjects, 45 with post-traumatic stress disorder (PTSD) and 17 healthy control subjects, were examined in a study of serotonin function measured by [3H]paroxetine binding to platelet membranes. Subjects were selected from male combat exposed veterans. The mean (+/- S.D.) Kd was 0.078 +/- 0.045 nM for the PTSD patient group and 0.064 +/- 0.037 nM for the control group. The mean Bmax was 934 + 238 fmol/mg protein for the PTSD patient group and 1011 +/- 363 fmol/mg protein for the control group. There was no significant difference between the groups for either Kd or Bmax before or after controlling for season of sampling. There were no significant differences between subjects with current PTSD and those with PTSD in the past, or between PTSD subjects with or without concurrent major depressive disorder. This study finds no relationship between PTSD, major depressive disorder and peripheral serotonin function measured by [3H]paroxetine binding to blood platelets.

Prolactin response to low-dose dexamethasone challenge in combat-exposed veterans with and without posttraumatic stress disorder and normal controls

The prolactin and cortisol responses to dexamethasone (0.5 mg) were studied in combat veterans with (n = 18) and without (n = 12) posttraumatic stress disorder (PTSD) and normal controls (n = 18). Both veteran groups demonstrated greater prolactin suppression than the normals. In contrast, only veterans with PTSD showed an enhanced cortisol suppression in response to dexamethasone. These findings suggest that the prolactin response to dexamethasone may reflect a feature of combat exposure rather than PTSD per se.

Childhood abuse, alexithymia and personality disorder

I examined the relationships among childhood abuse, alexithymia, and personality disorder. Participants were 60 adults who were receiving outpatient psychotherapy. Both the participants and their therapists used the Toronto Alexithymia Scale to provide independently information concerning the client's level of alexithymia. The therapists provided information concerning DSM-III-R personality disorder diagnoses, and participants completed portions of the Personality Diagnostic Questionnaire-Revised. Information concerning childhood abuse history was obtained from the therapists. As expected, childhood abuse, alexithymia, and personality disorder were all associated with each other. The abilities to identify and communicate emotions were differentially associated with childhood abuse and personality disorder.

Platelet serotonin transporter in children and adolescents with obsessive-compulsive disorder or Tourette's syndrome

Previous studies of serotonin transporter protein (5HTPR) indexed in platelets by 3H-imipramine demonstrate reduction in children with comorbid obsessive-compulsive disorder (OCD) and Tourette's syndrome (TS).

OBJECTIVE

To use the 5HTPR selective ligand 3H-paroxetine and homogeneous diagnostic groups to reevaluate these findings.

METHOD

Platelet Kinetic binding parameters were evaluated using standard techniques from medication-free child and adolescent patients with OCD (n = 18), with TS (n = 10), and normal controls (n = 19).

RESULTS

Baseline binding capacity (Bmax) was significantly reduced in patients with OCD (1,342 +/- 952 fmol/mg; protein p < .01) compared with normal controls (2,486 +/- 1309 fmol/mg) and TS patients (2,420 +/- 1,069 fmol/mg; p < .05). Among OCD patients who were subsequently treated on an open-label basis with selective serotonin reuptake inhibitor (SSRI), Bmax values at baseline differentiated between responders (1,718 +/- 1,041 fmol/mg) and nonresponders (802 +/- 713 fmol/mg protein; p < .05). Response to SSRI was greatest in patients with a positive family history of OCD. Among responders (n = 10), baseline Yale-Brown Obsessive Compulsive Scale and Bmax were positively correlated (r = .76, p = .01), as was Clinical Global Impression (r = .67, p = .03).

CONCLUSIONS

Platelet 5HTPR capacity (Bmax) is reduced in children and adolescents with OCD, but not in those with TS. 5HTPR may be an indirect measure of basal serotonergic tone.

Cardiovascular, neuroendocrine, and monoaminergic responses to psychological stressors: possible differences between remitted panic disorder patients and healthy controls

Both clinical symptomatology and stress research suggest that panic attacks might be partially attributable to exaggerated psychophysiological responses to environmental stressors. In the present study, we aimed to explicitly test this idea by measuring the physiological responses to a mild psychological stressor in both healthy controls (n = 8) and fully remitted, medication-free panic disorder patients (n = 8). One hour before the stressor, former patients, compared to healthy controls, exhibited higher diastolic blood pressure. From a blood sample taken 30 min before the stressor, patients, compared to controls, had lower paroxetine platelet binding site densities. During the stressor, patients, compared to controls, had greater increases in plasma levels of cortisol. These preliminary findings suggest that remitted panic disorder patients might have disturbed physiological responses to mild psychological stressors. These disturbances might be related to the development of future episodes.

Platelet imipramine binding in patients with posttraumatic stress disorder before and after phenelzine treatment

Posttraumatic stress disorder (PTSD) is frequently associated with major depressive disorder, and antidepressants have been reported to ameliorate PTSD symptoms in some patients. The present study assessed the number and affinity of platelet imipramine binding sites, as a marker of the serotonin transporter complex, in PTSD male patients (n = 10) before and after phenelzine treatment (30-60 mg/day, for 4 weeks) as well as in comparison to healthy controls (n = 10). In our sample, there was no evidence of a significant difference in the characteristics (Bmax and Kd) of platelet [3H]imipramine binding between the PTSD patients and the controls and within PTSD patients before and after phenelzine treatment. Moreover, no beneficial effect of phenelzine was detected in the patients (as assessed by PTSD, anxiety, and depression scales).

A review of the psychobiology and pharmacotherapy of posttraumatic stress disorder

OBJECTIVE

To review the literature on certain psychobiologic elements of posttraumatic stress disorder (PTSD) as they pertain to possible pharmacotherapeutic interventions.

METHOD

The literature pertaining to the neuroanatomical, neurochemical, and cellular elements was reviewed. As well, both controlled and uncontrolled studies of pharmacotherapy in PTSD were analyzed.

RESULTS

The literature suggests that the stress response triggers certain neuromodulators with subsequent psychoneurological restructuring; that various antidepressants have been demonstrated to be effective for treatment of criterion B symptoms; that, to date, a single antidepressant has been demonstrated to be effective in a controlled trial for criterion C symptoms; and that, to date, in controlled trials, antidepressants and a benzodiazepine have proved effective for criterion D symptoms.

CONCLUSION

Currently, a comprehensive approach requires multimodel understanding and multimodal treatment.

Treatment of posttraumatic stress disorder: a review

This article analyzes the literature on the treatment of posttraumatic stress disorder (PTSD). It briefly exposes the theoretical basis for each treatment modality and extensively examines pharmacological, behavioral, cognitive, and psychodynamic therapies, as well as group and family therapies, hypnosis, inpatient treatment, and rehabilitation. Articles were identified by scanning Medline and PsychLit for all papers in English reporting treatment of PTSD. Anecdotal case reports were, then, excluded. Eighty one articles were identified and categorized as either biological or psychological, with the latter category further divided into behavioral, cognitive, psychodynamic, and other treatment modalities. Information regarding the type of trauma, the sample studied, the treatment method, and the results of the treatment has been extracted from each article and is presented briefly. A synthesis of findings in each area is provided. Most studies explored a single treatment modality (e.g., pharmacological, behavioral). The cumulated evidence from these studies suggests that several treatment protocols reduce PTSD symptoms and improve the patient's quality of life. The magnitude of the results, however, is often limited, and remission is rarely achieved. Given the shortcoming of unidimensional treatment of PTSD, it is suggested that combining biological, psychological, and psychosocial treatment may yield better results. It is further argued that rehabilitative goals should replace curative techniques in those patients with chronic PTSD. A framework for identifying targets for each treatment modality is presented.

Hypodensity of platelet serotonin uptake sites in posttraumatic stress disorder: associated clinical features

We have previously reported that binding to blood platelets of paroxetine, a selective serotonin (5-HT) reuptake inhibitor which binds to 5-HT uptake sites, is decreased in patients with posttraumatic stress disorder (PTSD). Specifically, we found a lower number of platelet 3H-paroxetine binding sites (Bmax) and a lower dissociation constant (Kd) for 3H-paroxetine binding in combat veterans with PTSD compared to normal control subjects. In the current study we assessed the relationship of platelet 3H-paroxetine binding to clinical features in 41 Vietnam combat veterans with SCID-diagnosed PTSD. The results indicated that Bmax of platelet 3H-paroxetine binding was negatively correlated with both state and trait anxiety, as well as with depressive and overall PTSD symptoms. However, there was no evidence that platelet 3H-paroxetine binding differed as a function of comorbid psychiatric diagnoses including major depression, other anxiety disorders, and substance abuse in these patients.

Platelet [3H]‐paroxetine binding in obsessive‐compulsive disorder

Platelet [3H]‐paroxetine binding was analysed in 26 patients (13F, 13M) with obsessive compulsive disorder and 26 normal controls (13F, 13M). For patients with obsessive compulsive disorder, Bmax was 2127 ± 480 fmol/mg protein (mean±SD) compared to control Bmax values of 1926 ± 696 fmol/mg protein. The mean Kd value for the patients was 0.075 ± 0.025 nM and for the controls was 0.076 ± 0.032 nM. Analysis of covariance indicated a significant effect of sex on both Kd and Bmax but no effect of diagnosis (obsessive compulsive disorder versus normal controls) or season of sampling. The data provide no evidence for an abnormality of the platelet uptake mechanism as assessed by the measurement of [3H]‐paroxetine binding to the platelet transporter in obsessive compulsive disorder.

Platelet [3H]paroxetine binding in panic disorder

Platelet [3H]paroxetine binding was measured in 20 patients (14 females, six males) with panic disorder and 20 normal controls (14 females, six males). For patients with panic disorder, Bmax was 1987 +/- 1135 fmol/mg protein (mean +/- SD) compared with control Bmax values of 1626 +/- 611 fmol/mg protein. The mean Kd value for the patients was 0.076 +/- 0.056 nM and for the controls was 0.083 +/- 0.033 nM. ANCOVA indicated no significant effect of sex, diagnosis (panic disorder vs. normal controls) or season of sampling on either Kd or Bmax. The data provide no evidence for an abnormality of the platelet uptake mechanism in panic disorder.

[3H]paroxetine binding to platelets of patients with social phobia: comparison to patients with panic disorder and healthy volunteers

Recent studies suggest that serotonergic functioning may be aberrant in patients with social phobia. Capacity of the serotonin (5-HT) transporter, as determined by 3H-paroxetine binding, was measured in 18 drug-free patients with generalized social phobia and compared to 15 drug-free patients with panic disorder and 23 healthy control subjects. The density (Bmax) and affinity (1/Kd) of 3H-paroxetine binding sites was similar in all three groups. To the extent that the serotonin transporter in platelets and neurons is comparable, these findings suggest that this aspect of serotonergic function is normal in patients with social phobia.

Platelet paroxetine binding and fluoxetine pharmacotherapy in posttraumatic stress disorder: preliminary observations on a possible predictor of clinical treatment response

Recent open clinical trials have found the selective serotonin reuptake inhibitor (SSRI) fluoxetine to be beneficial in the treatment of posttraumatic stress disorder (PTSD) symptoms. We have reported previously that the binding of a newer SSRI, paroxetine, to blood platelets is decreased in PTSD patients compared to normal control subjects. In the current study, pretreatment platelet paroxetine binding data were analyzed for ten Vietnam combat veterans who were treated clinically with fluoxetine for PTSD, diagnosed on the basis of the Structured Clinical Interview for DSM-III-R. Specific binding of 3H-paroxetine is reported in terms of the dissociation constant (Kd) and the maximum density of binding sites (Bmax). Based on our previous findings we hypothesized that decreased platelet 3H-paroxetine binding would be associated with positive therapeutic response to subsequent treatment with fluoxetine. Global clinical improvement ratings, conducted blind to the biochemical data, were used to separate patients into five maximal responders and five partial responders. The results indicated that maximal responders had lower pretreatment Kd values (p = .016) and a trend toward lower pretreatment Bmax values (p = .075) than the partial responders. These preliminary findings may warrant further study of platelet SSRI binding as a possible predictor of SSRI treatment response in PTSD patients.