Panic attacks and the dexamethasone suppression test

Le test de stimulation par le corticotrophin-releasing factor chez les patients présentant des attaques de panique

Les convergences épidémiologiques, cliniques et biologiques, entre trouble panique et dépression laissent à penser que ces 2 phénomènes pourraient être sous-tendus par un même mécanisme physiopathologique. Des travaux récents retrouvent chez des patients présentant un trouble panique une diminution de la réponse de l'ACTH à la stimulation par le CRF (corticotropin-releasing factor) exogène comparable à celle observée dans la population des déprimés endogènes. Ces résultats suggèrent l'existence dans le trouble panique, comme dans la dépression, d'un hyperfonctionnement de l'axe hypothalamo-hypophyso-surrénalien sous l'influence d'une hypersécrétion de CRF endogène. Afin de vérifier cette hypothèse, les auteurs ont pratiqué un test de stimulation par le CRF et un test de freinage par la dexaméthasone (DST) chez 10 patients non déprimés présentant un trouble panique ou une agoraphobic avec attaques de panique. Les résultats du DST n'apparaissent pas différents de ceux habituellement retrouvés chez le sujet sain. La comparaison des taux de base de Cortisol et d'ACTH retrouvés dans le groupe « panique » et chez 7 sujets témoins ne montre pas de différence. Enfin, si la réponse du Cortisol à la stimulation par le CRF exogène n'apparaît pas significativement différente de celle observée chez les témoins, on note une augmentation de la réponse de l'ACTH chez les sujets présentant des attaques de panique. Ces résultats sont en contradiction avec ceux des travaux précédemment cités et semblent infirmer l'existence dans les troubles anxieux paroxystiques d'une hypersécrétion chronique de CRF endogène. Ces discordances peuvent, certes, peut-être s'expliquer par des différences dans les populations étudiées et dans les méthodes utilisées. L'augmentation de la réponse de l'ACTH à la stimulation par le CRF exogène observée dans cette étude chez les patients présentant des attaques de panique se montre cepcndant compatible, contrairement aux autres travaux, avec les théories habituellement admiscs et impliquant une hyperactivité noradrénergique centrale dans l'étiopathogénie des troubles anxieux.

Platelet serotonin binding and plasma cortisol in panic disorder before and after alprazolam plus behavioral guidance treatment

In 32 patients with panic disorder with or without agoraphobia, Bmax measures of 5-HT binding in platelets did not differ from normal controls at baseline. Plasmatic cortisol levels were significantly higher than controls in the morning and in the evening measures as well as in post-dexamethasone assays. Following an 8-week treatment period with alprazolam plus behavioral guidance encouraging exposure, Bmax values did not alter but cortisol measures diminished significantly. Measures of phobic avoidance were negatively correlated with 5-HT Bmax values. Plasmatic cortisol correlated positively with the number of situational panic attacks in the month before treatment. There were no correlations between cortisol and 5-HT Bmax measures. A possible link between serotonin function and phobic avoidance is discussed. Cortisol changes were interpreted as being related to the global severity of the anxious state.

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).

[Contributions of cortisol suppression tests to understanding of psychiatric disorders: a narrative review of literature]

Activity of the hypothalamic-pituitary-adrenal axis had been studied for the past half century, when some researchers noted that some patients with Cushing's syndrome and severe mood disorders had high baseline cortisol levels, which resulted in an inhibited response in the 1mg dexamethasone suppression test. Altered dexamethasone suppression test results were subsequently found in many psychiatric diseases, including anorexia nervosa, obsessive-compulsive disorder, degenerative dementia, bipolar disorders, and schizophrenia. The relationship between high baseline cortisol levels and stress has also been studied. Some researches on the genesis of borderline personality disorder focused on traumatic childhood backgrounds. Other investigations aimed at elucidating the relationship between traumatic backgrounds and some psychiatric disorders noted that patients with post-traumatic stress disorder and borderline personality disorder showed an enhanced cortisol suppression with low cortisol doses (0.5 mg). Recent studies showed that use of an ultra-low dose of cortisol during the dexamethasone suppression test may be helpful for detecting disorders with hyperactivity of the hypothalamic-pituitary-adrenal axis. Recent advances in neuroimaging support the existence of hyperactivity of the hypothalamic-pituitary-adrenal axis in patients with borderline personality disorder, relating a decreased pituitary gland volume to major traumatic backgrounds and suicidal attempts. The purpose of this paper is to make a narrative review of research using dexamethasone suppression test in psychiatric disorders, in order to ascertain its value as a supplemental diagnostic test or as a prognostic marker.

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.

Serotonin and the neuroendocrine regulation of the hypothalamic--pituitary-adrenal axis in health and disease

Serotonin (5-hydroxytryptamine, 5-HT)-containing neurons in the midbrain directly innervate corticotropin-releasing hormone (CRH)-containing cells located in paraventricular nucleus of the hypothalamus. Serotonergic inputs into the paraventricular nucleus mediate the release of CRH, leading to the release of adrenocorticotropin, which triggers glucocorticoid secretion from the adrenal cortex. 5-HT1A and 5-HT2A receptors are the main receptors mediating the serotonergic stimulation of the hypothalamic-pituitary-adrenal axis. In turn, both CRH and glucocorticoids have multiple and complex effects on the serotonergic neurons. Therefore, these two systems are interwoven and communicate closely. The intimate relationship between serotonin and the hypothalamic-pituitary-adrenal axis is of great importance in normal physiology such as circadian rhythm and stress, as well as pathophysiological disorders such as depression, anxiety, eating disorders, and chronic fatigue.

Mixed anxiety-depressive disorder and major depressive disorder: comparison of the severity of illness and biological variables

Mixed anxiety-depressive disorder (MADD) is a new diagnostic category defining patients who suffer from both anxiety and depressive symptoms of limited and equal intensity accompanied by at least some autonomic features. Patients do not meet the criteria for specific anxiety or depressive disorders. The emergence of the symptoms is independent of stressful life events. There are many issues presently under investigation about the validity of this clinical entity. In this study, a group of 29 patients with MADD was compared with a group of 31 patients with major depressive disorder (MDD) to assess the differences and similarities between these two disease categories in terms of severity measures and biological variables. The dexamethasone suppression test (DST) was employed, and thyroid hormones and thyrotropin (TSH) levels were measured for the evaluation of hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-thyroid (HPT) axes, respectively. The patients with MADD were found to be less depressive and more anxious compared to those with MDD. DST responses and thyroid functions were found to be similar in the two groups. When severity of depression was controlled, k(max) and 2300-h cortisol values were found to be significantly higher in the MADD group. Although the patients with MDD and MADD presented with relatively different clinical features, there is not enough biological evidence indicating that MADD represents a discrete diagnostic category. However, there may be relatively higher HPA activity in MADD patients.

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.

Differential responses to anxiogenic challenge studies in patients with major depressive disorder and panic disorder

Anxiogenic challenge studies (intravenous lactate infusion and oral fenfluramine challenge) were conducted in 17 patients with panic disorder (PD), 12 patients with major depressive disorder and a history of panic attacks (MDD-PD), 27 patients with major depression and no history of panic (MDD), and 12 normal controls. PD and MDD-PD patients revealed significantly greater anxiogenic responses to lactate infusion and fenfluramine administration than either MDD patients or controls. PD patients revealed the most robust anxiogenic responses to both challenges as well as associated significant prolactin and cortisol responses to fenfluramine. The findings suggest that the predisposition to panic attacks as seen in PD and MDD-PD patients may represent a distinct neurobiological diathesis which may coexist with a major depressive diathesis in some patients. The delineation of subgroups within the more heterogenous groups of patients with MDD and/or PD will lead to greater precision in the development of clinical treatment strategies. Thus, MDD-PD patients (better called panic-depressives) may have a more severe illness than patients with MDD alone which must be accounted for in the course of pharmacotherapy and psychotherapy.

Interactions of anxiolytic and antidepressant drugs with hormones of the hypothalamic-pituitary-adrenal axis

Changes in hormones of the hypothalamic-pituitary-adrenal (HPA) axis in patients suffering from anxiety and depressive disorders are reviewed, and the changes that occur when animals are exposed to test situations used preclinically to model anxiety or depression. The effects of exogenous administration of HPA hormones both clinically and in animal tests is discussed and the effects of clinically used anxiolytics and antidepressants on hormones of the HPA axis. The final section discusses stress-induced changes in the CNS.

Behavioral biochemical and neuroendocrine concomitants of lactate-induced panic anxiety

In a single-blind study using sodium lactate infusions to provoke panic attacks, 11 of 15 patients with panic disorder panicked with lactate. None of the 15 control subjects panicked during lactate administration. Before receiving lactate, higher preinfusion anxiety levels were present in the patient group as compared to controls. Preinfusion Acute Panic Inventory (API) scores were significantly higher in patients who panicked compared to nonpanicking patients. In addition, patients who panicked during lactate infusion showed a higher mean plasma MHPG level at baseline. During lactate infusion, however, no increase in plasma MHPG was seen in patients who panicked, nor in nonpanickers and controls. Several other biochemical and hormonal variables were measured. No single biochemical or neuroendocrine variable was found to correlate with lactate-induced panic attacks. It is argued that the baseline arousal level of patients with panic disorder may be increased, which renders these patients more vulnerable to panic attacks.

Dehydroepiandrosterone-sulfate/cortisol ratio in panic disorder

We hypothesized that the dehydroepiandrosterone-sulfate (DHEA-S)/cortisol ratio, which has been used as an index of adrenocortical function, would be altered in panic disorder patients and would change after treatment. We evaluated 10 male and 14 female outpatients meeting DSM-III-R criteria for panic disorder. Of these 24 subjects, 13 were treated with clonazepam, 8 were treated with alprazolam, and 3 were treated with placebo as part of a double-blind study. The DHEA-S/cortisol ratio values in the 24 patients with panic disorder (mean = 20.5, SD = 11.6) were significantly higher than those of a group of 60 normal controls (mean = 11.5, SD = 6.01) and were also significantly higher than those of a group of 22 depressed patients (mean = 10.6, SD = 6.33). Although there was no significant difference in the pretreatment DHEA-S/cortisol ratio values between male (mean = 23.6, SD = 11.8) and female (mean = 18.2, SD = 11.3) panic disorder patients, the effects of treatment on this ratio differed between the two sexes. In fact, in the female patients there was a significant decrease in the DHEA-S/cortisol ratio at the end of the study (mean = 15.1, SD = 7.9), while in the male patients there was no significant change in this ratio at the end of the study (mean = 30.2, SD = 21.4). No significant differences were noted between pretreatment and posttreatment DHEA-S/cortisol ratio values in patients treated with alprazolam (n = 8), in patients treated with clonazepam (n = 13), or in patients treated with placebo (n = 3).(ABSTRACT TRUNCATED AT 250 WORDS)

The significance of HPA axis disturbance in panic disorder

Agoraphobic and panic disorder patients underwent 1-mg Dexamethasone Suppression Tests (DST) before, during, and after an 8-week trial of diazepam, alprazolam, or placebo. Previously described, never-ill controls underwent similar testing. At baseline, 21 of 82 (25.6%) panic disorder and 5 of 38 (13.2%) controls were nonsuppressors. This difference grew more marked with multiple testing over a 2-month period; 18 of 44 (40.9%) panic disorder patients were nonsuppressors on at least 1 of 3 tests compared with only 5 of 35 (14.3%) controls (p = 0.006). DST results were related to severity, but not to the presence or absence, of depressive syndromes. Control for plasma dexamethasone levels left highly significant differences in postdexamethasone cortisol across diagnostic groups. Neither DST results nor plasma dexamethasone levels changed in concert with clinical change, and type of treatment had little differential effect on these measures. Nor did DST results predict subsequent course when active treatment was extended by 6 months. However, DST results during the initial 8 weeks of treatment were strongly related to relapse when medications were tapered, even though this occurred 6 months after the last DST.

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.

Secondary depression in panic disorder and agoraphobia. II. Dimensions of depressive symptomatology and their response to treatment

Secondary depressive symptomatology in 435 subjects with panic disorder and phobic avoidance was studied before and after alprazolam treatment. No subject who had a primary affective disorder was included. Calculation of Hamilton Depression Rating Scale factor scores revealed that the agitation/anxiety, sleep disturbance, and somatization factors accounted for approximately 75% of the HAM-D total score; these all showed significant improvement with alprazolam treatment. There were few differences in dimensions of depressive symptomatology between those subjects with and those without major depression; the main difference was in the overall intensity of the depression.

HPA axis disturbance and treatment outcome in panic disorder

Some patients with panic disorder exhibit an abnormal response to dexamethasone. As this phenomenon may reflect disturbances in the central noradrenergic system and as alprazolam may work through this system to produce improvement, we predicted a particularly robust response among nonsuppressors. Fifty-two patients with panic disorder or with agoraphobia with panic attacks were given alprazolam as the sole treatment during either of 2, 8-week, double-blind, placebo-controlled trials. Though baseline clinical severity predicted globally rated outcome, baseline Dexamethasone Suppression Test results did not.

Cortisol measures in primary major depressive disorder with hypersomnia or appetite increase

Morning plasma cortisol response to the 1 mg dexamethasone suppression test along with cortisol levels in blood, cerebrospinal fluid (CSF), and urine were measured in hospitalized male and female patients with primary major depressive disorder who reported hypersomnia (n = 23), or increase in appetite (n = 22). Comparisons were drawn to cortisol levels in patients with primary major depressive disorder who did not report hypersomnia or appetite increase (n = 23) and to normal controls (n = 23), all age- and sex-matched. Depressives with hypersomnia or increased appetite showed higher than normal 24-h urinary free cortisol concentrations. Depressed patients without hypersomnia or appetite increase had in addition to elevated free urinary cortisol concentrations higher than normal morning plasma cortisol levels before and after dexamethasone administration and a higher incidence of cortisol non-suppression after dexamethasone compared to normal subjects. The findings provide preliminary evidence that HPA activation in depression is diminished in the presence of hypersomnia and/or an increased appetite. Studies of the hypothalamic-pituitary-adrenal axis may be useful for differentiating subtypes of depression characterized by hypersomnia or enhanced appetite.

Biology of anxiety

Our understanding of the biological basis of anxiety is far from complete, although our knowledge of both the neuropharmacologic and molecular basis of anxiety has increased. This article reviews our current knowledge of the possible biological basis of generalized anxiety disorder and panic disorder.

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.

Altered plasma dexamethasone and cortisol suppressibility in patients with panic disorders

Some abnormalities in the hypothalamic-pituitary-adrenal (HPA) axis in patients with panic disorders were recently reported. The possibility that the disposition of dexamethasone, which has been reported to influence the Dexamethasone Suppression Test (DST), might be altered in this subgroup of patients has not, as yet, been reported. We report that 4:00 PM dexamethasone plasma concentrations following a 1-mg oral DST were significantly (p less than 0.01) lower in 23 patients with panic disorders (0.49 +/- 0.44 ng/ml) compared to 52 normal control subjects (1.09 +/- 0.64 ng/ml). This is in addition to the significantly higher (p less than 0.05) 4:00 PM postdexamethasone cortisol values per nanogram per milliliter of dexamethasone in the panic disorder patients compared to normal controls (17.7 +/- 29.6 versus 5.0 +/- 11.2 micrograms/dl). The mean percent suppression of cortisol from baseline in panic disorder was normal despite one-half the dexamethasone concentrations in these subjects. The cortisol suppression versus dexamethasone concentration curve was also shifted lower (greater fraction of cortisol suppression) and to the left (toward lower dexamethasone concentrations). These results further suggest that the HPA system is indeed altered in panic disorders, but in a manner that is not readily apparent from the DST alone.

Anxiety and the dexamethasone suppression test monitored with saliva

To assess the effect of anxiety on response to the Dexamethasone Suppression Test (DST), cortisol concentrations were determined in patients who had various diagnoses, with anxiety as a secondary characteristic. Saliva was collected before and after venepuncture at 4:05 PM following completion of the Leeds Questionnaire at 3:00 PM. Matrix effects, which caused an initial artefactual decrease in cortisol levels in some saliva samples in patients with high anxiety, could be eliminated by repeated freezing/thawing. There was no significant difference between salivary cortisol concentrations before and after venepuncture, indicating that variability in response to the DST is not a correlate of anxiety and stressful venepuncture. There was no association between anxiety scores and plasma or salivary cortisol values: thus, anxiety is unlikely to be a major contributory cause of nonsuppression of hypercortisolemia in the DST.

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

Abnormalities of the hypothalamic-pituitary-adrenal (HPA) axis and noradrenergic function have been reported in patients with panic disorder. Mean urinary free cortisol and plasma MHPG were measured in 12 medication-free panic disorder patients and 12 normal controls. No significant difference in urinary free cortisol and plasma MHPG was observed between the patients and controls. There was no relationship between plasma MHPG and urinary free cortisol in the panic patients or normal controls. These findings are described within the context of current concepts of stress and noradrenergic dysfunction in panic disorder.

The dexamethasone suppression test and plasma dexamethasone in generalized anxiety disorder

A Dexamethasone Suppression Test nonsuppression rate of 27% was found in a group of 30 generalized anxiety disorder patients before treatment. The dexamethasone concentrations in the eight nonsuppressors were significantly lower than in eight suppressors matched by sex and age, but were similar to those in five nonsuppressors from a matched normal control group. The dexamethasone concentrations in the generalized anxiety disorder suppressors and a matched group of eight normal control suppressors were similar. After successful nondrug behavioral treatment, all generalized anxiety disorder patients were suppressors. Posttreatment dexamethasone concentrations in the initial nonsuppressor patients remained significantly lower than in the initial suppressors. The results suggest that low plasma dexamethasone concentrations after 1 mg oral dexamethasone may confer a vulnerability to nonsuppression that may be expressed in the presence of high state anxiety.

Systemic hormonal and physiological abnormalities in anxiety disorders

Among the studies of systemic hormonal and physiological abnormalities associated with anxiety disorders, the most consistent and extensive findings suggest (a) peripheral adrenergic hyperactivity (including increases in norepinephrine but not epinephrine) and functional dysregulation, (b) increased incidence of mitral valve prolapse in panic patients, and (c) normal suppressibility of the hypothalamic-pituitary-adrenal cortical endocrine system with dexamethasone in panic patients. Other less-certain findings include (a) increased circulating concentrations of plasma ACTH and/or cortisol, and prolactin, in panic patients, (b) increased platelet monoamine oxidase activity in generalized anxiety and/or panic patients, (c) decreased gonadal axis activity in some anxious individuals, (d) decreased nighttime melatonin plasma concentrations in panic patients, and (e) peripheral alpha 2 and beta-adrenoreceptor down-regulation, with normal serotonin binding parameters. These findings, taken together, provide tentative support for dysfunction in adrenergic and GABAergic central nervous system mechanisms in people with anxiety disorders. Abnormal anxiety and normal stress both show evidence of adrenergic hyperactivity; however, there appear to be differences in hormonal profiles, especially the apparent lack of increase of epinephrine during panic attacks, as well as differences in the reactivity of the system, and in the "trigger" mechanisms which determine when the response occurs.

Antidepressants in panic disorder and agoraphobia

A survey of the literature on the use of antidepressants for treating patients with panic disorder and agoraphobia with panic attacks suggests that both tricyclic antidepressants and monoamine oxidase inhibitors have efficacy in blocking panic attacks. While we have witnessed dramatic progress in the pharmacological treatment of panic-related disorders over the past 20 years, many unresolved questions remain. Further understanding of dose-response relationships, optimal duration of treatment and predictors of relapse are needed to optimize pharmacological treatment of panic-related disorders. Studies comparing the relative efficacy and side effects spectrum of various effective medications are needed. It is not presently possible to specify which patients will require medication or behavioral treatment alone, and studies to date have incompletely examined this murky issue. Further prospective studies directly comparing the pharmacological and behavioral treatments will help further elucidate the relative contribution of each treatment and possibly clarify which patients require both treatments. Controlled studies in the future which standardize dosage and duration of treatment and use comparable, objective outcome variables promise to provide important theoretical and clinical information regarding the pharmacological treatment of panic-related disorders.

Serial dexamethasone suppression tests in simultaneous panic and depressive disorders

Recent work suggests that the simultaneous occurrence of major depressive disorder (MDD) and panic disorder (PD) may be of relevance for clinical findings, therapeutic outcome, and prognosis. It is of interest to know whether or not this relevance extends to biological findings. We addressed this question through comparison of serial Dexamethasone Suppression Test (DST) results in patients who had either MDD alone or simultaneous MDD and PD. We were unable to describe differences between the groups.

Platelet [3H]imipramine binding in patients with panic disorder

[3H]imipramine binding to platelets was measured in 17 drug-free panic disorder patients and 14 healthy controls. No difference in Bmax or Kd values was found between the two groups. Patients with a past history of major melancholic depression or severe agoraphobia had similar binding parameters as panic disorder patients without a history of depression or severe agoraphobia.

The dexamethasone suppression test in panic disorder and major depressive episodes

Dexamethasone Suppression Tests (DST) were performed on 30 patients with panic disorder and on 30 patients treated for major depressive episodes in order to seek an answer to the question of whether or not the two disorders have a common biological background. The hypothesis was based on the results of family studies known from the literature and on the favorable therapeutic response obtained with tricyclic antidepressants. Normal suppressive (i.e., negative in our terminology) DSTs were found in 16.7% of the patients with panic disorder and in 56.7% of patients suffering from major depressive episodes. The anxiety indices of the two groups differed significantly from each other. The results do not suggest the possibility of a close genetic relationship between the two conditions.

The dexamethasone suppression test in generalised anxiety disorder

The dexamethasone suppression test was performed on 79 patients with a diagnosis of generalised anxiety disorder. A non-suppression rate of 27% was obtained, comparable to that found in out-patient major depression but notably higher than previous reports in panic disorder. No good clinical predictors of non-suppression were discovered, nor was the co-occurrence of depression sufficient to account for the finding.

The effect of serum dexamethasone concentrations in the dexamethasone suppression test

Serum dexamethasone and cortisol concentrations were measured in a sample of 98 psychiatric inpatients during the course of the 1-mg oral overnight Dexamethasone Suppression Test (DST). Suppressors were found to have significantly higher serum dexamethasone concentrations than nonsuppressors at each time of sampling (8:00 AM, 4:00 PM, and 11:00 PM). There was a significant inverse curvilinear relationship between serum dexamethasone and cortisol concentrations at each sample time. Although serum dexamethasone concentration was a potent determinant of postdexamethasone serum cortisol concentration, there were still significantly higher serum concentrations of cortisol in patients with major depression compared with patients with other disorders when dexamethasone concentrations were statistically controlled. By taking serum dexamethasone concentrations into account in defining DST suppression status, a modest increase in diagnostic specificity was achieved, but no substantial change in sensitivity.

Dexamethasone concentrations and the dexamethasone suppression test in psychiatric disorders

The dexamethasone suppression test (DST) has been widely used in psychiatry as a laboratory aid for the diagnosis of endogenous depression; failure to suppress serum cortisol levels is interpreted as confirming a clinical diagnosis of endogenous depression. We found that serum dexamethasone concentrations in this test vary widely and are determinants of the DST response: non-suppression of serum cortisol levels is associated with low serum dexamethasone concentrations, and suppression is associated with high concentrations.

The biological basis of anxiety. An overview

The DSM-III divides anxiety disorders into two broad categories, Phobic Disorders and Anxiety States. Anxiety states characterised by panic attacks have been separated from generalised anxiety disorders. While this classification may not be generally accepted it is of heuristic value. Delineation of panic disorder as a distinct diagnostic entity has led to renewed efforts to identify a biological cause for the sudden severe somatic and psychological symptoms experienced by these patients. A review of evidence for the involvement of the major neurotransmitter systems is presented. Systematic investigations in DSM-III defined groups of patients are only beginning to be reported. It is difficult as yet to draw any definite conclusions, but some tentative evidence for abnormalities of the noradrenergic system and the GABA-benzodiazepine chloride ionophore receptor complex are emerging. The reliable induction of panic attacks by chemical agents provides the promise of a greater understanding of the possible biological mechanisms involved in this anxiety disorder.

Tritiated imipramine binding to platelets is decreased in patients with agoraphobia

Controversy exists regarding the relationship between anxiety states and major depression. We studied the binding of tritiated imipramine to platelet membranes in order to determine if patients with agoraphobia and panic attacks differed from depressed subjects or healthy volunteers on this biological parameter. Mean (+/- SD) Bmax and Kd values were significantly lower in patients with agoraphobia and panic attacks (787 +/- 276 fmole/mg protein and 0.35 +/- 0.14 nM, respectively) than in healthy volunteers (1237 +/- 201 fmole/mg protein and 0.71 +/- 0.37 nM, respectively). In addition, patients with agoraphobia and panic attacks had binding parameters that were similar to those of patients with bipolar or familial pure depressive disorder, but significantly lower than those of patients with depressive spectrum or sporadic depressive disorder. These findings have implications for both the nosology and pathophysiology of anxiety disorders.

Abnormal escape from dexamethasone suppression in agoraphobia with panic attacks

Patients who met DSM-III criteria for agoraphobia with panic attacks underwent dexamethasone suppression tests (DSTs) before, during, and after treatment with alprazolam or placebo. Similarly, outpatients with major depression were given multiple DSTs as they participated in a study of desmethylimipramine efficacy. The likelihood of an abnormal escape from dexamethasone was similar in the two diagnostic groups; nonsuppression was somewhat more likely among patients with primary depression, but comparisons with agoraphobic groups remained statistically insignificant. These results apparently did not reflect misclassification of primary depression patients as agoraphobics since a history of major depression was not related to the likelihood of nonsuppression within that group. Moreover, change in DST results during treatment reflected clinical change among agoraphobics. After a review of relevant followup and family studies, we conclude that panic disorder and primary depression are separate illnesses and that hypothalamic-pituitary-adrenal axis hyperactivity is an epiphenomenon of both.

A modified dexamethasone suppression test for endogenous depression

In order to simplify the dexamethasone suppression test (DST), we have administered a lower dosage of dexamethasone (DEX) and shortened the sampling time to a single morning blood sample. DEX (in dosage increments from 0.125 to 1.0 mg, p.o.) was administered at 2300 h to normal volunteers in a double-blind randomized fashion, and blood samples were taken at 0700 h the following morning. While significant cortisol suppression occurred after the 0.375 mg, 0.5 mg, and 1.0 mg doses of DEX, the 0.5 mg dose was the smallest that clearly suppressed cortisol in all eight subjects. This dose then was used to test the feedback sensitivity of the central nervous system (CNS)-pituitary-adrenal axis in endogenously depressed patients. Twenty endogenously depressed patients and 20 normal volunteers were given both the standard 1.0 mg DST, with post-DEX serum cortisol determined at 1500 h, and the simplified 0.5 mg DST, with post-DEX serum cortisol determined at 0700 h. Four patients (20%) and one control (5%) were nonsuppressors after the 1.0 mg DST, and nine patients (45%) and one control (5%) were nonsuppressors after the 0.5 mg DST. In addition, nine patients with major depression (nonendogenous subtype) and 15 patients with panic attacks also were studied using the 0.5 mg DST. Only 2 of these 24 patients (8%) were nonsuppressors. The results suggest that the single-sample 0.5 mg DST is more sensitive than the standard 1.0 mg DST, and the specificity of the modified test appears comparable to the standard form of the test.

Dexamethasone suppression test as a simple measure of stress?

Non-suppression of cortisol by dexamethasone has been described as a biological marker of a diagnostic subgroup of depressed patients. This paper presents the hypothesis that the degree of non-suppression is a variable that reflects the quantity of stress or distress experienced by the patient rather than relating to a specific diagnosis. Such a quantitative measure of stress would be valuable for research in general medicine as well as in psychiatry. Testing of this postulate should apply a more precise interpretation of endocrine principles than has been applied to the dexamethasone suppression test to date.

Agoraphobia and the dexamethasone suppression test: atypical depression?

The tricyclic antidepressants and the monoamine oxidase inhibitors have been shown to be effective in the treatment of some patients with phobic and panic disorders. To explain this action it has been suggested that a number of these patients may have an atypical biological depression. In an attempt to test this hypothesis we used the dexamethasone suppression test (DST), which has been proposed as a state dependent biological marker of depression. We compared the non-suppression rate of agoraphobic patients suffering panic attacks with controls and with patients suffering major depression. Twenty-nine per cent of the agoraphobics showed non-suppression compared with 12% of the control group and 64% of the depressives.

Abnormal dexamethasone suppression test in primary obsessive-compulsive patients: a confirmatory report

The dexamethasone suppression test (DST) was administered after baseline cortisol measurements in 20 patients (10 males, 10 females) who met DSM-III criteria for obsessive-compulsive disorder (OCD). Six patients (30%) showed an abnormal escape from dexamethasone suppression. DST suppressors vs. DST nonsuppressors showed no differences on age, rate of secondary depressive disorders, or scores on the Hamilton Rating Scale for Depression, the Minnesota Multiphasic Personality Inventory D scale, or OCD rating scales. Surprisingly, there was a trend for suppressors to have a stronger family history of depressive disorders, and for nonsuppressors to include an excess of male subjects. Moreover, there was a significant correlation between levels of cortisol before and after DST. In five of six nonsuppressors, both depressive symptoms and obsessive-compulsive behaviors showed a diminution in response to antidepressant therapy combined, in one case, with intensive behavior therapy. The relationships between OCD and endogenous depression, as well as the specificity of the DST, are discussed.