Normal urinary free cortisol and plasma MHPG in panic disorder: clinical and theoretical implications

Impact of Long-Rope Jumping on Monoamine and Attention in Young Adults

Previous research has shown that rope jumping improves physical health; however, little is known about its impact on brain-derived monoamine neurotransmitters associated with cognitive regulation. To address these gaps in the literature, the present study compared outcomes between 15 healthy participants (mean age, 23.1 years) after a long-rope jumping exercise and a control condition. Long-rope jumping also requires co-operation between people, attention, spatial cognition, and rhythm sensation. Psychological questionnaires were administered to both conditions, and Stroop task performance and monoamine metabolite levels in the saliva and urine were evaluated. Participants performing the exercise exhibited lower anxiety levels than those in the control condition. Saliva analyses showed higher 3-methoxy-4-hydroxyphenylglycol (a norepinephrine metabolite) levels, and urine analyses revealed higher 3-methoxy-4-hydroxyphenylglycol and 5-hydroxyindoleacetic acid (a serotonin metabolite) levels in the exercise condition than in the control. Importantly, urinary 5-hydroxyindoleacetic acid level correlated with salivary and urinary 3-methoxy-4-hydroxyphenylglycol levels in the exercise condition. Furthermore, cognitive results revealed higher Stroop performance in the exercise condition than in the control condition; this performance correlated with salivary 3-methoxy-4-hydroxyphenylglycol levels. These results indicate an association between increased 3-methoxy-4-hydroxyphenylglycol and attention in long-rope jumping. We suggest that long-rope jumping predicts central norepinephrinergic activation and related attention maintenance.

Smaller volume of right hippocampal CA2/3 in patients with panic disorder

The hippocampus is thought to play an important role in conveying contextual information to the amygdala as the neural basis of panic disorder (PD). Previous studies have revealed functional abnormalities in the hippocampus in patients with PD compared with healthy control subjects (HC), but no study has reported volume abnormalities in the hippocampus or evaluated minute structural changes in the hippocampus in such patients. We thus investigated volume abnormalities in the subfields of the hippocampus to better understand the neurobiological basis of PD. The hippocampus was extracted from structural brain magnetic resonance images obtained from 38 patients with PD and 38 HC and then segmented into six subfields. The relative volume of each subfield was compared between the two groups. The severity of symptoms was assessed using the Panic Disorder Severity Scale (PDSS) and social functioning was assessed using the Global Assessment of Functioning (GAF) scale. Our results revealed that patients with PD had a significantly smaller volume of the right cornu ammonis (CA) 2/3 hippocampal subfield compared with HC. No significant associations were found between the volumes of the right CA 2/3 and the PDSS or GAF scores in correlation analyses. In conclusion, CA2/3 is thought to be related to contextual memory function, and our results suggest that this particular hippocampal subfield plays a role in the development of PD symptoms.

Interoception, Stress, and Physical Symptoms in Stress-Associated Diseases

Abstract. The brain and peripheral bodily organs continuously exchange information. Exemplary, interoception refers to the processing and perception of ascending information from the body to the brain. Stress responses involve a neurobehavioral cascade, which includes the activation of peripheral organs via neural and endocrine pathways and can thus be seen as an example for descending information on the brain-body axis. Hence, the interaction of interoception and stress represents bi-directional communication on the brain-body axis. The main hypothesis underlying this review is that the dysregulation of brain-body communication represents an important mechanism for the generation of physical symptoms in stress-related disorders. The aims of this review are, therefore, (1) to summarize current knowledge on acute stress effects on different stages of interoceptive signal processing, (2) to discuss possible patterns of abnormal brain-body communication (i.e., alterations in interoception and physiological stress axes activation) in mental disorders and chronic physical conditions, and (3) to consider possible approaches to modify interoception. Due to the regulatory feedback loops underlying brain-body communication, the modification of interoceptive processes (ascending signals) may, in turn, affect physiological stress axes activity (descending signals), and, ultimately, also physical symptoms.

Peripheral Biomarkers in DSM-5 Anxiety Disorders: An Updated Overview

Anxiety disorders are prevalent and highly disabling mental disorders. In recent years, intensive efforts focused on the search for potential neuroimaging, genetic, and peripheral biomarkers in order to better understand the pathophysiology of these disorders, support their diagnosis, and characterize the treatment response. Of note, peripheral blood biomarkers, as surrogates for the central nervous system, represent a promising instrument to characterize psychiatric disorders, although their role has not been extensively applied to clinical practice. In this report, the state of the art on peripheral biomarkers of DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th edition) Anxiety Disorders is presented, in order to examine their role in the pathogenesis of these conditions and their potential application for diagnosis and treatment. Available data on the cerebrospinal fluid and blood-based biomarkers related to neurotransmitters, neuropeptides, the hypothalamic-pituitary-adrenal axis, neurotrophic factors, and the inflammation and immune system are reviewed. Despite the wide scientific literature and the promising results in the field, only a few of the proposed peripheral biomarkers have been defined as a specific diagnostic instrument or have been identified as a guide in the treatment response to DSM-5 Anxiety Disorders. Therefore, further investigations are needed to provide new biological insights into the pathogenesis of anxiety disorders, to help in their diagnosis, and to tailor a treatment.

Panic patients in the non-panic state: physiological and cognitive dysfunction

Panic attacks and the antipanic effect of antidepressants are claimed to distinguish panic disorder (PD) from generalised anxiety disorder. However, most studies showing neurochemical disturbances in PD overlook the non-panic state. We compared panic patients in the non-panic state with controls on biochemical, psychological and physiological measures. There were no differences on the neuroendocrine tests. Self-ratings of bodily and psychological symptoms of anxiety were significantly higher in patients and they scored worse on word recall. Patients had significantly more skin conductance fluctuations and slow wave activity in the electroencephalogram, a sign of hyperventilation which may have implications for brain activity. Discrepancies between patients' self-ratings and objective measures of pulse rate and psychomotor performance indicated that panic patients have distorted perceptions of both physical and mental functioning. Hyperventilation and cognitive distortions in the non-panic state may facilitate panic attacks and are part of the pathophysiology of PD.

Biological markers for anxiety disorders, OCD and PTSD: A consensus statement. Part II: Neurochemistry, neurophysiology and neurocognition

OBJECTIVE

Biomarkers are defined as anatomical, biochemical or physiological traits that are specific to certain disorders or syndromes. The objective of this paper is to summarise the current knowledge of biomarkers for anxiety disorders, obsessive-compulsive disorder (OCD) and posttraumatic stress disorder (PTSD).

METHODS

Findings in biomarker research were reviewed by a task force of international experts in the field, consisting of members of the World Federation of Societies for Biological Psychiatry Task Force on Biological Markers and of the European College of Neuropsychopharmacology Anxiety Disorders Research Network.

RESULTS

The present article (Part II) summarises findings on potential biomarkers in neurochemistry (neurotransmitters such as serotonin, norepinephrine, dopamine or GABA, neuropeptides such as cholecystokinin, neurokinins, atrial natriuretic peptide, or oxytocin, the HPA axis, neurotrophic factors such as NGF and BDNF, immunology and CO2 hypersensitivity), neurophysiology (EEG, heart rate variability) and neurocognition. The accompanying paper (Part I) focuses on neuroimaging and genetics.

CONCLUSIONS

Although at present, none of the putative biomarkers is sufficient and specific as a diagnostic tool, an abundance of high quality research has accumulated that should improve our understanding of the neurobiological causes of anxiety disorders, OCD and PTSD.

Effects of the cortisol stress response on the psychotherapy outcome of panic disorder patients

BACKGROUND

A proportion of patients with panic disorder (PD) fail to show a remission after psychotherapy. Biological correlates of psychotherapy non-response have rarely been described in the literature. The aim of the present study was to research the relationship between the cortisol stress response and the psychotherapy outcome in PD patients.

METHODS

Twenty-eight PD patients (20 females, mean age±SD: 35.71±13.18) seeking psychological treatment for PD and n=32 age- and sex-matched healthy control participants (21 females, aged 34.66±12.07) participated in this study. The patients underwent five weeks of cognitive behavioural therapy (CBT). Within the first two weeks of the CBT, both study groups were confronted with the Trier Social Stress Test (TSST). Blood sampling for cortisol and adrenocorticotropic hormone (ACTH) evaluation as well as fear-rating (Visual Analogue Scale; Primary Appraisal and Secondary Appraisal Questionnaire, PASA) accompanied the TSST. The global severity of PD (Panic & Agoraphobia Scale; PAS), agoraphobic cognitions (Agoraphobic Cognitions Questionnaire; ACQ), fear of bodily sensations (Bodily Sensations Questionnaire; BSQ), agoraphobic avoidance (Mobility Inventory; MI), and depressiveness (Beck Depression Inventory; BDI) were assessed before and after the CBT (except the BDI).

RESULTS

The statistical analysis revealed significant main effects of time for cortisol and the ACTH concentration in response to the TSST, independently of the study group. 42.9% of the PD patients and 65.6% of the healthy control participants showed a cortisol stress response to the TSST≥55.2nmol/l (descriptive finding). The data showed a significant inverse association of the TSST cortisol stress response with the MI total score when accompanied. Further, a significant association of the PASA subjective level of fear and the BSQ as well as a trend for an association of the PASA with the ACQ were observed.

CONCLUSION

Consistent with prior research, we could replicate findings of decreased cortisol concentrations in the PD patients in comparison to the healthy control participants. Furthermore, our findings agree with previous data showing an association of the attenuated cortisol stress response with the psychotherapy non-response. In the present sample, those patients with the lowest cortisol concentrations showed the least improvement in agoraphobic avoidance after psychotherapy. The patients with the highest level of fear showed the most improvement in fear of bodily sensations. Study limitations as well as implications for future studies will be discussed.

Plasma catecholamine levels before and after paroxetine treatment in patients with panic disorder

Catecholamines such as norepinephrine, epinephrine, and dopamine are closely related to the autonomic nervous system, suggesting that panic disorder may involve elevated catecholamine levels. This study investigated basal and posttreatment catecholamine levels in patients with panic disorder. A total of 29 patients with panic disorder and 23 healthy controls participated in the study. Panic disorder patients received paroxetine treatment for 12 weeks after clinical tests and examination had been conducted. We investigated the difference in basal levels of catecholamine and measured the changes in catecholamine levels before and after drug treatment in panic disorder patients. The basal plasma epinephrine (48.87±6.18 pg/ml) and dopamine (34.87±3.57 pg/ml) levels of panic disorder patients were significantly higher than those (34.79±4.72 pg/ml and 20.40±3.53 pg/ml) of the control group. However, basal plasma norepinephrine levels did not show statistically significant differences between patients and controls. After drug therapy, plasma catecholamine levels were nonsignificantly decreased and norepinephrine levels showed a tendency toward a decrease that did not reach significance. In conclusion, this study suggests the possibility of a baseline increase of plasma catecholamine levels and activation of sympathetic nervous systems in patients with panic disorder which may normalize after treatment with paroxetine.

Investigation of cortisol levels in patients with anxiety disorders: a structured review

Anxiety disorders are common and distressing medical conditions, which typically arise in adolescence or early adult life. They can persist for many years, reducing quality of life, limiting academic and occupational achievement, and being responsible for considerable economic pressures. Although a range of psychological and pharmacological treatments are available, their success is often limited, and many patients remain troubled by significant symptom-related disability for long periods. The detailed pathophysiology of each anxiety disorder is not established, and novel treatments that are based solely on current understanding of conventional neurotransmitter function are unlikely to be substantially more effective or better tolerated than current treatments. Investigations of hypothalamo-pituitary axis function across panic disorder, generalized anxiety disorder, specific phobias and social anxiety disorder have produced intriguing findings but not revealed a consistent pattern of endocrine disturbance, perhaps reflecting differences in methodology and the nature and size of the clinical samples. There is a persistent need for large, prospective studies using standardized methods for investigation and data analysis (164 words).

Gender effect on the relationship between stress hormones and panic-agoraphobic spectrum dimensions in healthy subjects

INTRODUCTION

Alterations of the hypothalamic-pituitary-adrenal (HPA) axis and of its peripheral indices have been reported in both normal and pathological anxiety with controversial findings. The aim of the present study was to investigate the possible correlations between serum cortisol and dehydroepiandrosterone-sulfate (DHEA-S) levels and DHEA-S/cortisol ratio, and panic-agoraphobic spectrum dimensions in a sample of healthy subjects.

METHODS

Forty-two healthy subjects of both sexes, with no current or lifetime psychiatric disorders, were assessed by means of the Structured Clinical Interview for DSM-IV (SCID-I/P) and the so-called Panic Agoraphobic Spectrum-Self Report lifetime version (PAS-SR).

RESULTS

Significant, negative correlations were found between cortisol levels and the total score of the separation sensitivity, panic-like symptoms, and medication/substance sensitivity PAS-SR domains. The PAS-SR total and the panic-like symptoms domain scores were positively related to the DHEAS/cortisol ratio. When the sample was divided in women and men, these correlations were present in women only.

DISCUSSION

These findings, while indicating the presence of significant relationships between panic-agoraphobic traits and some indices of HPA axis functioning in healthy women, would suggest this as one of the factors explaining the greater vulnerability of women to cross the line between normal and pathological anxiety.

CONCLUSIONS

Further studies are needed to explore gender differences in the relationships between HPA axis alterations and the panic-agoraphobic spectrum dimensions.

Elucidation of neurobiology of anxiety disorders in children through pharmacological challenge tests and cortisol measurements: a systematic review

Anxiety disorders are common both in adults and children. While there have been major advances in understanding the neurobiology of anxiety disorders in adults, progress has been more limited in the elucidation of the mechanisms underlying these disorders in childhood. There is a need to delineate childhood biological models, since anxiety represents a significant clinical problem in children and is a risk factor for the subsequent development of anxiety and depression in adulthood. We conducted a review of the literature regarding pharmacological challenge tests and direct hypothalamic-pituitary-adrenal axis measurement in children with anxiety disorders, with emphasis on panic disorder and social anxiety disorder. Studies identified were contrasted with those in adult panic disorder and social anxiety disorder. Despite this broad approach few studies emerged in children, with only 22 studies meeting inclusion criteria. When contrasted with adult neurobiological models of panic disorder and social anxiety disorder, children studied showed some abnormalities which mirrored those reported in adults, such as altered baseline respiration, altered responses to CO(2) challenge tests and blunted growth hormone response to yohimbine. However, results differed from adults with panic disorder and social anxiety in some aspects of noradrenergic and serotonergic function. For endpoints studied in panic disorder children, unlike adults, displayed a lack of baseline end-tidal CO(2) abnormalities and a different hypothalamic-pituitary-adrenal pattern response under low-dose CO(2). The biology of these anxiety disorders in children may only partially mirror that of adult anxiety disorders. However, caution is required as the evidence is limited, and many studies combined patients with panic disorder and social anxiety disorder with other disorders or non-specific anxiety. Further research is required to fully understand the biology and progression of childhood anxiety disorders.

Childhood stressful events, HPA axis and anxiety disorders

Anxiety disorders are among the most common of all mental disorders and their pathogenesis is a major topic in psychiatry, both for prevention and treatment. Early stressful life events and alterations of hypothalamic pituitary adrenal (HPA) axis function seem to have a significant role in the onset of anxiety. Existing data appear to support the mediating effect of the HPA axis between childhood traumata and posttraumatic stress disorder. Findings on the HPA axis activity at baseline and after stimuli in panic disordered patients are inconclusive, even if stressful life events may have a triggering function in the development of this disorder. Data on the relationship between stress, HPA axis functioning and obsessive-compulsive disorder (OCD) are scarce and discordant, but an increased activity of the HPA axis is reported in OCD patients. Moreover, normal basal cortisol levels and hyper-responsiveness of the adrenal cortex during a psychosocial stressor are observed in social phobics. Finally, abnormal HPA axis activity has also been observed in generalized anxiety disordered patients. While several hypothesis have attempted to explain these findings over time, currently the most widely accepted theory is that early stressful life events may provoke alterations of the stress response and thus of the HPA axis, that can endure during adulthood, predisposing individuals to develop psychopathology. All theories are reviewed and the authors conclude that childhood life events and HPA abnormalities may be specifically and transnosographically related to all anxiety disorders, as well as, more broadly, to all psychiatric disorders.

Associations between DSM-IV diagnosis, psychiatric symptoms and morning cortisol levels in a community sample of adolescents

PURPOSE

Dysfunction of the hypothalamic-pituitary-adrenocortical axis (HPA-axis) is implicated in a variety of psychiatric and emotional disorders. In this study, we explore the association between HPA-axis functioning, as measured by morning cortisol, and common psychiatric disorders and symptoms among a community sample of adolescents.

METHOD

Data from a cross-sectional school-based survey of 501 school pupils, aged 15, were used to establish the strength of association between salivary morning cortisol and both diagnosis of psychiatric disorders and a number of psychiatric symptoms, as measured via a computerised psychiatric interview. Analysis, conducted separately by gender, used multiple regressions, adjusting for relevant confounders.

RESULTS

With one exception (a positive association between conduct disorder symptoms and cortisol among females) there was no association between morning cortisol and psychiatric diagnosis or symptoms. However, there was a significant two-way interaction between gender and conduct symptoms, with females showing a positive and males a negative association between cortisol and conduct symptoms. A further three-way interaction showed that while the association between cortisol and conduct symptoms was negative among males with a few mood disorder symptoms, among females with many mood symptoms it was positive.

CONCLUSIONS

Except in relation to conduct symptoms, dysregulation of morning cortisol levels seems unrelated to any psychiatric disorder or symptoms. However, the relationship between cortisol and conduct symptoms is moderated by both gender and mood symptoms. Findings are compatible with the recent work suggesting research should concentrate on the moderated associations between gender, internalising and externalising symptoms and cortisol, rather than any simple relationship.

Pregnant women's cortisol is elevated with anxiety and depression - but only when comorbid

Elevated cortisol during pregnancy is associated with adverse birth outcomes and may alter fetal development and subsequent adult health. Numerous studies link elevated cortisol to depression and anxiety, but only a few have examined these relationships during pregnancy and in response to laboratory stressors. No studies have investigated the impact of comorbid anxiety and depression on cortisol during pregnancy. Salivary cortisol samples were collected twice before and once after a set of computer-based tasks (Stroop color-word matching task and either mental arithmetic or a controlled breathing task) from 180 pregnant women at approximately 36 weeks gestation. Based on psychiatric diagnoses, four groups of women were compared: 121 control, 16 depression, 34 anxiety, and 9 comorbid. Women also completed symptom and stress self-report scales. There was a significant main effect for maternal diagnosis on cortisol levels. Post hoc comparisons showed that comorbid subjects had higher salivary cortisol levels than controls, but subjects with only one diagnosis did not. Similar to cortisol, the comorbid subjects also had higher ratings on pregnancy-specific distress. Comorbidity during pregnancy, versus depression or an anxiety disorder alone, is uniquely associated with elevated cortisol and a negative evaluation of pregnancy. The potential impact of this combined psychiatric diagnosis on fetal development and future adult health needs further investigation.

Salivary cortisol is associated with diagnosis and severity of late-life generalized anxiety disorder

Age-associated alterations in hypothalamic-pituitary-adrenal (HPA) axis functioning may make individuals more susceptible to HPA dysregulation in the context of mood and anxiety disorders. Little to no research has been done to examine HPA axis function in generalized anxiety disorder (GAD), particularly in late-life GAD, the most prevalent anxiety disorder in the elderly. The study sample consisted of 71 GAD subjects and 40 nonanxious comparison subjects over 60 years of age. We examined the hypotheses that elderly individuals with GAD will have elevated salivary cortisol levels compared to nonanxious subjects, and that elevated cortisol levels in GAD will be associated with measures of symptom severity. We report that late-life GAD is characterized by elevated basal salivary cortisol levels, with higher peak cortisol levels and larger areas under the curve, compared to nonanxious subjects. Additionally, severity of GAD as measured by the GAD Severity Scale and the Penn State Worry Questionnaire are positively correlated with cortisol levels. These data demonstrate HPA axis dysfunction in late-life GAD and suggest the need for additional research on the influence of aging on HPA axis function in mood and anxiety disorders.

Effects of experimental panic on neuroimmunological functioning

OBJECTIVE

Psychoimmunological research in panic disorder (PD) so far focussed on single time point evaluation in resting conditions. No robust evidence for changes in the immune system was found using this method. However, PD is characterized by the occurrence of unexpected panic attacks (PAs). The current research focuses on cytokine and acute phase protein (APP) levels and mitogen-induced cytokine secretion following 35% CO(2) inhalation-induced panic.

METHODS

Eighteen PD patients and 18 matched healthy control subjects underwent both a placebo and a 35% CO(2) inhalation on separate days. Blood samples for cytokine and APP determination were taken before and after the inhalation. In addition to serum determination, whole blood samples were cultured and stimulated with mitogens for assessment of the functional capacity of the immune system.

RESULTS

The 35% CO(2) inhalation induced significantly higher levels of anxiety in PD patients as compared to the control subjects, but no differences in immune parameters were found, either in basal conditions or after experimental panic induction.

CONCLUSION

In our sample we do not find any changes in serum levels or functional capacity of several immunological parameters in the experimentally provoked PAs. Similar results have been found in social phobia, whereas in other affective disorders such as depression and posttraumatic stress disorder, immune changes are evident. Changes seem to coincide with alterations in hypothalamic-pituitary-adrenal (HPA) axis function. Therefore, the bidirectional communication pathway between the immune system and the HPA axis might play a role in some affective disorders, but it does not specifically seem to be involved in the etiology of PD.

HPA axis activity in patients with panic disorder: review and synthesis of four studies

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis may play a role in panic disorder. HPA studies in patients with panic disorder, however, have produced inconsistent results. Seeking to understand the inconsistencies, we reexamined endocrine data from four studies of patients with panic disorder, in light of animal data highlighting the salience of novelty, control, and social support to HPA axis activity. Patients with panic disorder were studied (1) at rest over a full circadian cycle, (2) before and after activation by a panicogenic respiratory stimulant (doxapram) that does not directly stimulate the HPA axis, and (3) before and after a cholecystokinin B (CCK-B) agonist that is panicogenic and does directly stimulate the HPA axis. Patients with panic disorder had elevated overnight cortisol levels, which correlated with sleep disruption. ACTH and cortisol levels were higher in a challenge paradigm (doxapram) than in a resting state study, and paradigm-related ACTH secretion was exaggerated in patients with panic disorder. Panic itself could be elicited without HPA axis activation. Patients with panic disorder showed an exaggerated ACTH response to pentagastrin stimulation, but this response was normalized by prior exposure to the experimental context or psychological preparation to reduce novelty and enhance sense of control. Novelty is one of a number of contextual cues known from animal work to activate the HPA axis. The HPA axis abnormalities seen in patients with panic disorder in the four experiments reviewed here might all be due to exaggerated HPA axis reactivity to novelty cues. Most of the published panic/HPA literature is consistent with the hypothesis that HPA axis dysregulation in panic is due to hypersensitivity to contextual cues. This hypothesis requires experimental testing.

Psychoendokrinologie der Angst

Zusammenfassung. Ätiologie, Symptomatik und Verlauf von Angststörungen sind multikausal zu erklären. Ein Teilaspekt der psychobiologischen Erklärungsansätze von Angststörungen sind endokrine Auffälligkeiten, anhand derer bestimmte Unterformen pathologischer Angst charakterisiert werden können. Vor allem die Hypothalamus-Hypophysen-Nebennierenrinde-Achse und das sympathiko-adrenomedulläre System werden im Zusammenhang mit Emotionsregulation und pathologischer Angst untersucht. Beide Hormonsysteme spielen bei der Anpassung an individuelle Belastungssituationen eine bedeutende Rolle und beeinflussen die psychobiologische Anpassung an angstauslösende Situationen nachhaltig. In dieser Überblicksarbeit werden endokrine Dysregulationen der o.g. Hormonsysteme für verschiedene Unterformen von Angststörungen aufgezeigt und bzgl. ihrer ätiologischen Bedeutsamkeit, auch unter Berücksichtigung genetischer Befunde, diskutiert. Darüber hinaus werden erste therapeutische Ansätze, bei denen psychoendokrinologische Methoden genutzt werden, aufgezeigt.

Anxiety disorders: noradrenergic neurotransmission

The past decade has seen a rapid progression in our knowledge of the neurobiological basis of fear and anxiety. Specific neurochemical and neuropeptide systems have been demonstrated to play important roles in the behaviors associated with fear and anxiety-producing stimuli. Long-term dysregulation of these systems appears to contribute to the development of anxiety disorders, including panic disorder, posttraumatic stress disorder (PTSD), and social anxiety disorder. These neurochemical and neuropeptide systems have been shown to have effects on distinct cortical and subcortical brain areas that are relevant to the mediation of the symptoms associated with anxiety disorders. Moreover, advances in molecular genetics portend the identification of the genes that underlie the neurobiological disturbances that increase the vulnerability to anxiety disorders. This chapter reviews clinical research pertinent to the neurobiological basis of anxiety disorders. The implications of this synthesis for the discovery of anxiety disorder vulnerability genes and novel psychopharmacological approaches will also be discussed.

Neuroanatomical circuits modulating fear and anxiety behaviors

OBJECTIVE

Our understanding of the neurobiology of anxiety disorders, although not complete, has advanced significantly with the development and application of genetic, neuroimaging and neurochemical approaches.

METHOD

The neuroanatomical basis of anxiety disorders is reviewed with particular focus on the amygdala and the temporal and prefrontal cortex. The functional anatomical correlates of anxiety disorders such as panic disorder, specific phobias and post-traumatic stress disorder are also discussed.

RESULTS

Functional neuroimaging studies in patients with anxiety disorders have shown neurophysiological abnormalities during symptom provocation tests, implicating the limbic, paralimbic and sensory association regions. The involvement of neurotransmitters such as serotonin and norepinephrine in depressive disorders is well established. Antidepressants that affect these neurotransmitter systems have also been shown to be useful in the treatment and management of patients with anxiety disorders. The role of serotonin and norepinephrine in the pathophysiology of anxiety disorders is reviewed. In addition, the involvement of the stress hormone corticotropin-releasing hormone, the peptide cholecystokinin and the amino acid transmitter gamma-amino butyric acid in anxiety disorders is reviewed.

CONCLUSION

The inconsistency in the results of biologic investigations of anxiety disorders highlights the importance of addressing the neurobiologic heterogeneity inherent within criteria-based, psychiatric diagnoses. Understanding of this heterogeneity will be facilitated by the continued development and application of genetic, neuroimaging and neurochemical approaches that can refine anxiety disorder phenotypes and elucidate the genotypes associated with these disorders. Application of these experimental approaches will also facilitate research aimed at clarifying the mechanisms of anti-anxiety therapies.

Salivary cortisol response during exposure treatment in driving phobics

OBJECTIVE

Extensive research on the hypothalamic-pituitary-adrenal (HPA) axis response to stress has not clarified whether that axis is activated by phobic anxiety. We addressed this issue by measuring cortisol in situational phobics during exposure treatment.

METHODS

Salivary cortisol was measured in 11 driving phobics before and during three exposure sessions involving driving on crowded limited-access highways and compared with levels measured in 13 healthy controls before and during two sessions of driving on the same highways. For each subject, data collected in the same time period on a comparison nondriving day served as an individual baseline from which cortisol response scores were calculated.

RESULTS

Cortisol levels of driving phobics and controls did not differ on the comparison day. Phobics also had normal cortisol response scores on awakening on the mornings of the exposures but these were already increased 1 hour before coming to the treatment sessions. Phobics had significantly greater cortisol response scores during driving exposure and during quiet sitting periods before and afterward. These greater responses generally paralleled increases in self-reported anxiety. At the first exposure session, effect sizes for differences in cortisol response scores between the two groups were large. Initial exposure to driving in the first session evoked the largest responses.

CONCLUSION

The data demonstrate that the HPA axis can be strongly activated by exposure to, and anticipation of, a phobic situation.

[Cortisol in night-urine: Introduction of a research method in psychoneuroendocrinology]

Cortisol is one of the major parameters investigated in psychoneuroendocrinological research, but the methods employed for sample collecting are often unsatisfactory. A suitable method of sample collection should allow for the integrative assessment of long-term changes of the HPA-system, should be non-invasive, and should not exceed the subject's compliance. The assessment of cortisol in night-urine fulfils these demands; although this method has been occasionally employed, it has not yet been described systematically. For the first time a detailed description is given here that allows for a standardized replication. In ten previous studies and three investigations of our own this method has been successfully applied to detect changes in the cortisol excretion of patients with endocrinological and psychiatric disorders as well as in subjects under conditions of psychosocial stress. The determination of cortisol in night-urine represents an ideal method for the assessment of changes in the basal HPA-activity in numerous areas of psychoneuroendocrinological research, e.g. field and screening studies in natural environment, clinical studies in psychiatry and especially follow-up studies in psychotherapy research.

Diurnal variation of cortisol in panic disorder

In patients with panic disorder (n=23), daytime salivary cortisol levels were determined in 2-h spans on 3 consecutive days and compared with 23 age- and sex-matched healthy controls. Additionally, nocturnal urinary free cortisol levels were measured. Daytime salivary cortisol levels were numerically higher in the patients, although the difference did not reach statistical significance. In a subgroup of 14 patients with higher illness severity (as expressed by a score >/=22 on the Panic and Agoraphobia Scale), salivary cortisol levels were significantly higher than in the controls. Mean nocturnal urinary cortisol levels were significantly higher in the whole group of patients and also in the more severely ill subgroup when compared with controls. Cortisol elevations seem to be more pronounced during the night and occurred mainly in more severely ill panic patients.

Saliva level of free 3-methoxy-4-hydroxyphenylglycol (MHPG) as a biological index of anxiety disorders

To access the saliva level of free 3-methoxy-4-hydroxyphenylglycol (MHPG) as a biological index of anxiety disorders, gender- or age-dependent changes in saliva MHPG level in patients with anxiety disorders were investigated. Saliva MHPG levels in 196 normal volunteers (59 male, 137 female) and 42 outpatients with anxiety disorders (20 male, 22 female) at the initial consultation to the hospital were measured by gas chromatography-mass spectrometry. Saliva MHPG levels in patients were higher than those in normal subjects. The increase in saliva MHPG levels in male patients was greater than that in female patients. Age-associated increase in the saliva MHPG level was greater in patients than in normal subjects. Especially, a significant interaction of age vs. patient effect was found in female subjects (P=0.0005), but not in male subjects (P=0. 174). These data indicate that the measurement of saliva MHPG would be valuable for detecting pathological anxiety in male patients regardless of age and in older female patients, but not in younger female patients.

The Neurobiological Basis of Anxiety and Fear: Circuits, Mechanisms, and Neurochemical Interactions (Part II)

This article is Part II of a review of the neuronal circuits, neural mechanisms, and neuromodulators that seem to be involved in anxiety and fear states. Part I focused on the specific brain structures, including the roles of the amygdala, locus coeruleus, hippocampus, and various cortical regions and the neural mechanisms of fear conditioning, extinction, and behavioral sensitization in mediating the signs and symptoms of anxiety and fear. Part II attempts to develop a better understanding of neurochemical mediation of traumatic remembrance and the neurobiological consequences of stress, particularly when experienced early in life. Finally, the data is synthesized to provide a basis for understanding the pathophysiology of anxiety disorders, such as Panic disorder and Posttraumatic Stress Disorder. NEUROSCIENTIST 4:122–132, 1998

The relationship between plasma MHPG and NE: employing regression models in estimating centrally derived MHPG and peripheral NE turnover rate in panic disorder

Studies investigating the role of the noradrenergic system in the pathophysiology of anxiety have focused on measuring plasma 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) levels. Fewer studies have examined norepinephrine levels. Basal plasma norepinephrine and free MHPG levels were simultaneously measured in 33 normal controls and 20 panic disorder (PD) patients. Norepinephrine levels were similar in patients and controls, but MHPG levels were significantly lower in patients (13.34 +/- 3.22 vs 18.37 +/- 4.49 pmol ml-1, p < 0.0001). Norepinephrine correlated significantly with plasma MHPG levels in controls (r = 0.538, p < 0.0001) and patients (r = 0.645, p < 0.002). Patients had a trend toward a lower y-intercept than controls, suggesting a lower contribution by the CNS to MHPG pool plasma levels (9.18 vs 12.51, p < 0.08). Norepinephrine turnover rate was similar in patients and controls. We propose that the dysregulation in the noradrenergic system in PD may be akin to animal studies of acute-on-top-of-chronic stress paradigms, whereby chronic stress results in normal or decreased basal NE turnover and sensitized responses to recurrent stresses.

Plasma vanillylmandelic acid level as an index of psychological stress response in normal subjects

The relationships between psychological stress responses and plasma levels of vanillylmandelic acid (VMA), 3-methoxy-4-hydroxyphenylglycol (MHPG), homovanillic acid (HVA), and 5-hydroxyindolacetic acid (5-HIAA) were investigated in normal volunteers. Two questionnaires were used to measure stress: the Psychological Stress Response Scale (PSRS) and the State-Trait Anxiety Inventory (STAI). Plasma levels of VMA--but not MHPG, HVA, and 5-HIAA--showed significant positive correlations with PSRS emotional and cognitive-behavioral stress and STAI state anxiety. Significant positive correlations were also found between plasma levels of VMA and MHPG and psychological stress responses measured repeatedly in a longitudinal study of an Olympic swimmer. Plasma VMA measurements, which reflect the level of activity of the peripheral sympathetic nervous system, may provide a useful biochemical index of psychological stress responses in normal subjects.

Noradrenergic mechanisms in stress and anxiety: II. Clinical studies

Studies in animals have shown a relationship between alterations in noradrenergic brain system function and behaviors of anxiety and fear. These findings have generated the hypothesis that the symptoms seen in patients with anxiety disorders may be related to alterations in noradrenergic function. A number of clinical studies have tested this hypothesis, utilizing measures of catecholaminergic function such as heart rate and blood pressure, measurement of norepinephrine and its metabolites in urine and plasma and adrenergic receptor binding in platelets, as well as pharmacological challenge to the noradrenergic system. Acute stressors, such as public speaking, have been associated with an increase in heart rate, blood pressure, and norepinephrine and its metabolites in urine and plasma. Findings in patients with panic disorder at baseline related to heart rate, blood pressure, baseline norepinephrine and its metabolites, and platelet adrenergic receptors have been mixed, while the most consistent findings have been blunted growth hormone response to clonidine and increased 3-methoxy-4-hydroxy-phenylethylene-glucol (MHPG) and anxiety following stimulation of the noradrenergic system with yohimbine. Baseline measures of noradrenergic function in patients with posttraumatic stress disorder (PTSD) have also been mixed, while an increased heart, blood pressure and norepinephrine response to traumatic reminders, as well as increased behavioral (as well as different brain metabolic) response to yohimbine, have been found in PTSD. There are fewer studies of noradrenergic function in the other anxiety disorders, and the findings there have not been consistent. These studies provide evidence for increased noradrenergic responsiveness in panic disorder and PTSD, although there does not appear to be an alteration in baseline noradrenergic function in these patients.

Hypothalamic-pituitary-adrenal axis activity in panic disorder: effects of alprazolam on 24 h secretion of adrenocorticotropin and cortisol

Pre-clinical and some clinical evidence suggests that central overdrive within the hypothalamic-pituitary-adrenal (HPA) axis may play a role in panic disorder, and that the anti-panic efficacy of alprazolam may involve its ability to inhibit this drive. Detailed examination of 24 h secretion of adrenocorticotropin (ACTH) and cortisol in 20 panic patients had revealed subtle HPA axis abnormalities prior to treatment. In order to determine whether these abnormalities resolve with alprazolam therapy, these patients were re-studied over a full circadian cycle after 12 weeks on alprazolam. Alprazolam produced substantial improvement in clinical status which was accompanied by nearly full resolution of pre-treatment hypercortisolemia. The impact of treatment on ACTH was more complex and influenced by symptom severity. The results are consistent with the hypotheses that HPA axis regulation is subtly disturbed in panic disorder and that impact on the HPA axis may play a role in alprazolam's mechanism of efficacy.

Cerebrospinal fluid gamma-aminobutyric acid in patients with panic disorder

Cerebrospinal fluid (CSF) gamma-aminobutyric acid (GABA) levels were measured in 11 patients with panic disorder (PD) prior to and following 7 months of treatment with alprazolam or imipramine and in six neurological control patients. Although a clear treatment response was observed in patients with PD, neither alprazolam nor imipramine significantly changed CSF GABA during the treatment period. A negative correlation was demonstrated between baseline CSF GABA and posttreatment overt psychopathology. Low pretreatment level of CSF GABA correlated significantly with poor therapeutic outcome, judged by the amount of anxiety and depression as well as by the frequency of panic attacks at the end of follow-up.

Normal urinary free cortisol and postdexamethasone cortisol in social phobia: comparison to normal volunteers

In primates, social stress is associated with activation of the hypothalamic-pituitary-adrenal (HPA) axis. Social phobia is a common, often disabling, form of pathological anxiety characterized by marked distress in situations involving possible scrutiny or evaluation. Little is known about HPA function in patients with social phobia. We examined 24-hour excretion of urinary free cortisol (UFC) in 54 patients with social phobia and post-dexamethasone cortisol levels in 64 patients with social phobia and found no evidence of HPA-axis overactivity compared to normal controls, despite pathological levels of anxiety.

The effects of physostigmine infusion on patients with panic disorder

Nine patients who met both DSM-III and RDC criteria for panic disorder and nine age-matched normal controls received infusions of physostigmine. The patients and normal controls did not differ in either their self-reported or the observer-reported ratings of anxiety, mood, or activation. The two subject groups also did not differ in blood pressure, pulse, or cortisol responses to physostigmine. Physostigmine did not provoke panic attacks in either the control or patients groups.

Cerebrospinal fluid levels of monoamine metabolites in panic disorder

The cerebrospinal fluid (CSF) levels of the serotonin metabolite 5-hydroxyindoleacetic acid (5HIAA), the noradrenaline metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG), and the dopamine metabolite homovanillic acid (HVA) did not differ significantly in a group of patients with panic disorder (n = 17) as compared to age- and sex-matched normal controls (n = 17). While CSF concentrations of HVA and 5HIAA were significantly correlated in both patients and controls, CSF MHPG levels were significantly correlated with the concentrations of CSF 5HIAA and HVA only in patients. In a small number of subjects (n = 5), successful reduction of anxiety attacks by administration of clomipramine or imipramine (50-150 mg/day) for at least 2 months was associated with a significant decrease in CSF concentrations of 5HIAA and MHPG, but not HVA.

Comparison of panic disordered patients with high versus low MHPG

Fourteen panic disorder patients with low 3-methoxy-4-hydroxyphenylglycol (MHPG) were compared to 14 patients with high MHPG. Patients with low MHPG were more likely during the preceding month to have experienced spontaneous panic attacks (P less than 0.008) than were patients with high MHPG. Patients with high MHPG had increased severity ratings on several individual symptoms of anxiety.

Effect of yohimbine on plasma homovanillic acid in panic disorder patients and normal controls

The effects of oral yohimbine (20 mg) or placebo or both drugs on plasma homovanillic acid (HVA) were evaluated in patients with panic disorder and normal controls. Panic disorder patients had similar HVA values at baseline compared with normal controls, and yohimbine failed to produce appreciable changes in HVA in both groups. These findings are discussed within the context of catecholaminergic theories of panic disorder.

Adrenergic status in anxiety disorders: platelet alpha 2-adrenergic receptor binding, blood pressure, pulse, and plasma catecholamines in panic and generalized anxiety disorder patients and in normal subjects

In order to evaluate adrenergic function in anxiety disorders, platelet alpha 2-adrenergic binding parameters and supine and standing blood pressure, pulse, and venous plasma epinephrine and norepinephrine were determined in patients with panic attacks or generalized anxiety disorder and in normal subjects. The maximum number of binding sites (Bmax) for the partial agonist tritiated clonidine was significantly lower for both patient groups than for normal subjects, and the Bmax for the antagonist tritiated yohimbine was significantly lower for panic patients. There were no other substantive differences across groups. Prior exposure to psychotropic drugs might account for the results for clonidine binding, but not for yohimbine. The Bmax for clonidine was correlated with norepinephrine increases upon standing and, for panic patients, with the severity of full unexpected panic attacks. These data provide further evidence of adrenergic receptor abnormalities in people with anxiety disorders.

Generalized anxiety disorder: some biochemical aspects

Fifty-one patients who met DSM-III criteria for generalized anxiety disorder, and who were recruited to participate in a drug outcome study, filled out a variety of rating scales and had blood samples drawn for plasma norepinephrine, epinephrine, and free 3-methoxy-4-hydroxyphenylglycol (MHPG) after a 20-min rest period. This group was compared to 15 normal controls who also had their blood drawn after a 20-min rest period. While the two groups were initially found to have significantly different levels of plasma free MHPG through the use of t tests, this finding was not confirmed by subsequent discriminant analysis.

Influences on cortisol and noradrenergic turnover of healthy controls and depressed patients during L-tryptophan loading

To investigate the interrelationships between the noradrenergic and serotonergic systems and the hypothalamic-pituitary-adrenal (HPA) axis, we measured the excretion of 3-methoxy-4-hydroxyphenylglycol (MHPG) and free cortisol (UFC) in 24-h urine both before and after loading with 2 g L-tryptophan (L-TRP) orally in 24 healthy controls and 33 depressed patients categorized according to DSM-III. Loading with L-TRP reduced MHPG excretion significantly by 56% in major depressives, whereas in healthy controls and in minor depressives no significant effects were observed. Although basal MHPG did not differ among these study groups, loading with L-TRP resulted in MHPG excretion in major depressives being significantly lower than in healthy controls and minor depressives. Loading with L-TRP increased UFC significantly by 49% only in major depressives with associated features. After L-TRP those patients exhibited significantly increased UFC as compared with all other depressives and controls, whereas basal UFC values did not differ among the study groups. In baseline conditions there were no significant correlations between MHPG and UFC excretion.

The corticotropin-releasing hormone test in patients with posttraumatic stress disorder

To evaluate the hypothalamic-pituitary-adrenal (HPA) axis in patients with posttraumatic stress disorder (PTSD), we measured adrenocorticotropin hormone (ACTH) and cortisol responses following administration of corticotropin-releasing hormone (CRH) in 8 combat veterans with chronic PTSD. The PTSD patients had a significantly lower ACTH response to CRH compared to a control group of normal volunteers. Blunted ACTH responses occurred in patients with PTSD alone, as well as those PTSD patients who also had major depression. The cortisol response, although reduced, was not significantly different from normal. The blunted ACTH response to CRH in PTSD patients is similar to that seen in other psychiatric disorders, such as depression, panic disorder, and anorexia nervosa.

Neuroendocrine effects of ovine corticotropin-releasing hormone in panic disorder patients

A number of neuroendocrine abnormalities have been reported in panic disorder patients: the most extensively studied being disturbances of hypothalamic-pituitary-adrenal function (Curtis et al. 1982; Leiberman et al. 1983; Uhde et al. 1988). The recent sequencing and synthesis of corticotropin-releasing hormone now allows direct testing of pituitary responsivity to this neuropeptide in affective and panic disorder patients (Holsboer et al. 1984; Gold et al. 1986; Roy-Byrne et al. 1986; Holsboer et al. 1987; Risch et al. 1988). We report the effects of intravenously administered ovine corticotropin-releasing hormone (0.03 micrograms/kg) on plasma concentrations of adrenocorticotropin hormone (ACTH) and cortisol in a small group of panic disorder patients and age- and sex-matched normal controls.

Biogenic amines and their metabolites in body fluids of normal, psychiatric and neurological subjects

The biogenic monoamines and their metabolites have been isolated, identified and quantified in human body fluids over the past forty years using a wide variety of chromatographic separation and detection techniques. This review summarizes the results of those studies on normal, psychiatric and neurological subjects. Tables of normal values and the methods used to obtain them should prove to be useful as a reference source for benchmark amine and metabolite concentrations and for successful analytical procedures for their chromatographic separation, detection and quantification. Summaries of the often contradictory results of the application of these methods to psychiatric and neurological problems are presented and may assist in the assessment of the validity of the results of experiments in this field. Finally, the individual, environmental and the methodological factors affecting the concentrations of the amines and their metabolites are discussed.

Basal adrenocortical activity and DST in electrodermally differentiated subgroups of panic patients

Twenty nine patients with panic disorder or agoraphobia with panic attacks were studied. The relationship between pre- and postdexamethasone serum cortisol level and electrodermal lability as reflected in electrodermal habituation rate and resting non-specific electrodermal activity was investigated. The frequency of non-suppression of cortisol following dexamethasone (DST non-suppressors) (at 5 micrograms/dl cut-off level) was 29.6% for the total group of patients. The basal plasma cortisol concentration showed positive correlation with the electrodermal habituation rate. The basal plasma cortisol level of slow habituator panic patients was significantly higher compared to rapid habituator patients, and it was above the normal range. On the contrary in rapid habituator panic patients the pre- and postdexamethasone cortisol difference was significantly less than in slow habituator patients, due to the normal basal plasma cortisol level and the relatively reduced rate of feedback suppression of cortisol following dexamethasone. Of the rapid habituator panic patients, 50% were non-suppressors following dexamethasone (at 5 micrograms/dl cut-off level). The above results might reflect two relatively different patterns of hypothalamic-pituitary-adrenal dysregulation in connection with two extremes of electrodermal habituation rate in panic patients.

Cortisol response to clonidine in panic disorder: comparison with depressed patients and normal controls

Abnormalities in regulation of noradrenergic function have been proposed as part of the pathology of depressive and panic anxiety disorders. However, abnormalities in hypothalamic-pituitary-adrenal (HPA) axis function have largely been limited to patients with depressive disorders. Using the cortisol response to clonidine, an alpha 2-adrenergic receptor agonist, this study examined the relationship between the noradrenergic system and the HPA axis in 10 patients with major depression (4 unipolar, 6 bipolar), 10 patients with panic disorder, and 10 normal controls. Baseline cortisol was significantly elevated in depressed as compared with panic patients, but not with controls. Depressed patients also tended to exhibit a greater absolute fall in plasma cortisol (5.2 +/- 4.0 micrograms/dl) compared with panic patients (1.7 +/- 2.4 micrograms/dl) (p less than 0.06, t-test). When expressed as a percentage of baseline, however, the cortisol response to clonidine did not differ significantly between diagnostic groups (p greater than 0.10). Basal levels of cortisol were highly correlated with the degree of decrease in cortisol induced by clonidine in the group of 30 subjects (r = -0.81, p less than 0.0001). These findings are discussed in the context of the utility of clonidine as a probe of the functional relatedness of the noradrenergic system and the HPA axis in these disorders.

Cerebral ventricular size in panic disorder

Computed axial brain tomography was studied in 25 patients with panic disorder. Patients had normal ventricular-brain ratio (VBR) compared to published norms. There was a significant association between VBR and duration of benzodiazepine use.