Medically unexplained dyspnoea and panic.

Medically unexplained dyspnoea in the pulmonary setting is often accompanied by considerable levels of anxiety, suggestive of psychopathology, in particular panic disorder (PD). This pilot study investigates the value of the Multidimensional Dyspnea Profile as a tool to facilitate identification of a specific dyspnoea profile suggestive of comorbid PD. The verbal descriptors, feeling depressed, air hunger and concentrating on breathing, significantly differentiated between the two groups of patients with pulmonary disease with and without PD.

Nicotine effects on human affective functions: a systematic review of the literature on a controversial issue.

The observation that nicotine modulates negative affectivity and has a mood enhancing effect mainly derives from studies conducted in the general population and in clinical samples, mostly in nicotine-deprived subjects. It has been explained by the so called deprivation-reversal hypothesis (i.e.

Brainstem response to hypercapnia: a symptom provocation study into the pathophysiology of panic disorder.

Background: The biological basis of uncued panic attacks is not yet understood. An important theory concerning the nature and cause of panic disorder is the 'suffocation false alarm theory'. This alarm is supposed to be over-sensitive in panic disorder patients and can be triggered by CO2.

Effect of the serotonin transporter gene and of environment on the continuity of anxiety and depression traits throughout adolescence.

Aims. Many studies of various stress reactive phenotypes suggest that 5-HTTLPR short allele carriers (S-carriers) are characterised by the stable trait of negative affectivity that is converted to psychopathology only under conditions of stress. In this study, we examined the moderating role of the 5-HTTLPR on the relationship between two objective chronic risk factors, i.

The weight of cognitions in panic: the link between misinterpretations and panic attacks.

In cognitive theory it is hypothesized that panic attacks are provoked by catastrophic misinterpretations of bodily sensations. The aim of the present study was to investigate the ability of associated word pairs referring to catastrophic thinking (e.g.

Carbon dioxide inhalation as a human experimental model of panic: the relationship between emotions and cardiovascular physiology.

Inhaling carbon dioxide (CO2)-enriched air induces fear and panic symptoms resembling real-life panic attacks, the hallmark of panic disorder. The present study aimed to describe the emotional and cardiovascular effects evoked by inhaling CO2, taking shortcomings of previous studies into account. Healthy volunteers underwent a double inhalation of 0, 9, 17.

On the psychotropic effects of carbon dioxide.

It has been well established that the inhalation of Carbon Dioxide (CO2) can induce in humans an emotion closely replicating spontaneous panic attacks, as defined by current psychiatry nosology. The purpose of this review is to provide a critical summary of the data regarding CO2's psychopharmacological properties and underlying mechanisms. The authors review the literature on the human and animal response for the exposure of exogenous CO2 focusing on five points of interest: 1) the early history of the use of CO2 as an anesthetic and therapeutic agent, 2) the subjective effects of breathing CO2 at different concentrations in humans, 3) the use of CO2 in experimental psychiatric research as an experimental model of panic, 4) the pharmacological modulation of CO2-induced responses, and 5) the putative neurobiological mechanisms underlying the affective state induced by CO2.

The role of "interoceptive" fear conditioning in the development of panic disorder.

More than 20% of the general population experience a panic attack at least once in their lives; however, only a minority goes on to develop panic disorder (PD). Conditioning mechanisms have been proposed to explain this evolution in persons who are susceptible to developing panic disorder upon a "traumatic" panic attack. According to preparedness theory, some cues are more likely to condition than others, namely, those referring to internal, bodily signals of danger.

35% CO2 sensitivity in social anxiety disorder.

The 35% carbon dioxide (CO(2)) challenge is a well-established model of panic. This study aimed to investigate 35% CO(2) sensitivity in patients with social anxiety disorder (SAD) compared with patients with panic disorder (PD) and normal controls. First, a 35% CO(2) challenge was conducted including 16 patients with generalized SAD, 16 with PD and 16 normal subjects.

Effects of acute exercise on CO(2) -induced fear.

Background: Acute exercise has shown to reduce the effects of experimental panic provocation in healthy volunteers and in patients with panic disorder. Recent evidence suggests that when larger amounts of CO(2) are inhaled, a large proportion of healthy subjects can also develop an affective response consistent with definitions of a panic attack. Our aim was to test whether exercise can show antipanic effects in healthy subjects when exposed to higher concentrations of CO(2).

Effects of tryptophan depletion and tryptophan loading on the affective response to high-dose CO2 challenge in healthy volunteers.

Rationale: It has been reported that in panic disorder (PD), tryptophan depletion enhances the vulnerability to experimentally induced panic, while the administration of serotonin precursors blunts the response to challenges.

Objectives: Using a high-dose carbon dioxide (CO(2)) challenge, we aimed to investigate the effects of acute tryptophan depletion (ATD) and acute tryptophan loading (ATL) on CO(2)-induced panic response in healthy volunteers.

Methods: Eighteen healthy volunteers participated in a randomized, double-blind placebo-controlled study.

Challenging anxiety: a focus on the specificity of respiratory symptoms.

Physiological symptoms are characteristic features of anxiety states. Presumably, specific psychophysiological profiles differentiate between anxiety disorders, which would offer potential for diagnostic purposes. Abundant evidence points to a causal relationship between panic disorder and instability of respiratory regulation.

Assessment of the emotional responses produced by exposure to real food, virtual food and photographs of food in patients affected by eating disorders.

Background: Many researchers and clinicians have proposed using virtual reality (VR) in adjunct to in vivo exposure therapy to provide an innovative form of exposure to patients suffering from different psychological disorders. The rationale behind the 'virtual approach' is that real and virtual exposures elicit a comparable emotional reaction in subjects, even if, to date, there are no experimental data that directly compare these two conditions. To test whether virtual stimuli are as effective as real stimuli, and more effective than photographs in the anxiety induction process, we tested the emotional reactions to real food (RF), virtual reality (VR) food and photographs (PH) of food in two samples of patients affected, respectively, by anorexia (AN) and bulimia nervosa (BN) compared to a group of healthy subjects.

Genetic moderation of CO2-induced fear by 5-HTTLPR genotype.

Inhalation of an increased concentration of carbon dioxide (CO(2)) has been shown to induce a state of negative affect in healthy subjects that is closely related to the clinical phenomenon of panic. It has been suggested that the vulnerability to CO(2) is moderated by differences in serotonin (5-HT) activity, caused by a functional polymorphism in the promoter region of the 5-HT transporter (5-HTTLPR) gene. Our aim was to examine the relationship between bi- and tri-allelic 5-HTTLPR genotype and the affective response to different dosages of inhaled CO(2) in healthy volunteers.

Nonhomogeneous results in place learning among panic disorder patients with agoraphobia.

Patients affected by panic disorder with agoraphobia (PDA) often suffer from visuo-spatial disturbances. In the present study, we tested the place-learning abilities in a sample of 31 PDA patients compared to 31 healthy controls (CTR) using the computer-generated arena (C-G Arena), a desktop-based computer program developed at the University of Arizona (Jacobs et al 1997, for further detail about the program, see http://web.arizona.

Cigarette smoking and panic: a critical review of the literature.

Objective: Cigarette smoking increases the risk of panic disorder with or without agoraphobia's emerging. Although the cause of this comorbidity remains controversial, the main explanations are that (1) cigarette smoking promotes panic by inducing respiratory abnormalities/lung disease or by increasing potentially fear-producing bodily sensations, (2) nicotine produces physiologic effects characteristic of panic by releasing norepinephrine, (3) panic disorder promotes cigarette smoking as self-medication, and (4) a shared vulnerability promotes both conditions. The aim of this review was to survey the literature in order to determine the validity of these explanatory models.

Cigarette smoking and 35% CO(2) induced panic in panic disorder patients.

Background: A disproportionately large number of persons with panic disorder (PD) smoke cigarettes compared to people in the general population and individuals with other anxiety disorders. Clinical and epidemiological data suggest that cigarette smoking increases the risk for the development and maintenance of PD. The carbon dioxide (CO(2)) challenge is well established as experimental model for panic.

Respiratory patterns in panic disorder reviewed: a focus on biological challenge tests.

Objective: To provide a systematic review of studies investigating respiration in PD and comments on relative inconsistencies.

Method: A Medline search of controlled studies focusing on pCO(2), respiratory rate, tidal volume, and minute volume in PD patients was conducted for baseline/resting condition, challenge, and recovery phase. Respiratory variability and comparisons between panickers and non-panickers were also examined.

Acids in the brain: a factor in panic?

Several methods to experimentally induce panic cause profound acid-base disturbances. Evidence suggests that CO(2) inhalations, lactate infusions and, to a certain extent, voluntary hyperventilation can conceivably lead to a common scenario of brain acidosis in the face of disparate intravascular pH alterations. The importance of this event is reflected in data that support a model in which experimental panic attacks, as proxy to those occurring spontaneously, constitute a response to acute brain acidosis.

Selective processing of social stimuli in the superficial amygdala.

The human amygdala plays a pivotal role in the processing of socially significant information. Anatomical studies show that the human amygdala is not a single homogeneous structure but is composed of segregable subregions. These have recently been functionally delineated by using a combination of functional magnetic resonance imaging (fMRI) and cytoarchitectonically defined probabilistic maps.

Negative affectivity in smokers applying to smoking cessation clinics: a case-control study.

Objective: The objective of this study was to assess whether subjects applying to smoking cessation clinics display a higher level of affective symptoms than smokers recruited from the general population.

Methods: The study was conducted according to a cross-sectional, case-control design. Cases were smokers applying to public smoking cessation clinics for the first time and controls were smokers recruited from the general population.

Objective and subjective measures in recovery from a 35% carbon dioxide challenge.

Objectives: Because hyperventilation, dyspnea, and a feeling of choking are often core features of a panic attack, respiration has been one of the most widely studied physiological parameters in panic disorder (PD) patients. A respiratory subgroup of PD, with distinct etiological pathways, has also been suggested. Investigation of the recovery phase following a respiratory challenge may be a reliable way to establish respiratory impairment in PD patients.

Desynchrony of fear in phobic exposure.

Intuitively, phobic exposure would seem to be a very stressful experience. However, it is not clear whether the characteristic feature of a classic stress response, activation of the hypothalamic-pituitary-adrenal (HPA) axis, is present in phobic fear. Some instances of phobic fear have been found to be accompanied by robust increases in cortisol, whereas in other instances a dissociation between subjective-behavioural arousal and the HPA-axis has been found.

Effect of buspirone on the behavioral regulation of rats in low versus high anxiety conditions.

Introduction: Buspirone (CAS 33386-08-2) is reported to have anxiolytic effects in humans and is mostly described for mild anxiety. To further explore the effects of buspirone on different levels of anxiety, the effect of buspirone was evaluated in two different conditions of the open field which were distinguished as low and high anxiety (enclosed and exposed open field, respectively).

Materials And Methods: Twenty-eight albino Wistar rats (350-400 g) were tested in two different arena settings, an enclosed and an exposed open field.