Caffeine challenge and breath-holding duration in patients with panic disorder

Correlations of plasma oxytocin with clinical and hormonal parameters in panic disorder

AIMS

The potential association between oxytocin (OXT) plasma levels and clinical and hormonal parameters in panic disorder (PD) especially in its acute phase - has not been investigated as yet. This was the aim of this article.

METHOD

Twenty-four consecutively-referred, acutely-ill, medication-free PD patients with (PDA, N = 21) or without agoraphobia, moreover without comorbidities, completed the following clinical measures: Hamilton Anxiety Rating Scale (HARS); Agoraphobic Cognitions Questionnaire (ACQ); Mobility Inventory-Alone subscale (MI-alone); and number of panic attacks during last 21 d (PA21d). Plasma levels of OXT, adrenocorticotropic hormone (ACTH) and cortisol were evaluated.

RESULTS

OXT levels were significantly, negatively associated with the HARS scores (r= -0.59 p=.002) and weakly, negatively correlated with the ACQ scores (r = -0.403 p=.051). No significant correlations were traced between OXT levels and PA21d, MI-alone, ACTH, and cortisol.

CONCLUSION

In acutely-ill, medication-free PD patients, OXT plasma levels may be relevant to the severity of their 'general' anxiety symptoms, but not to the 'specific' panic psychopathology.

Pituitary-adrenal axis hormones in early-onset versus late-onset panic disorder

OBJECTIVE

It has been hypothesised that early-onset panic disorder (PD) may constitute a biologically distinct subtype of PD, but the few relevant data are inconclusive. We systematically explored for potential psychopathological and hormonal differences between early-onset (age at onset ≤ 27 years) versus late-onset PD, in consecutively-referred, medication-free, acutely-ill PD outpatients, moreover without comorbid mental disorders except agoraphobia (N = 54; age = 32.3 ± 7.5 years; early-onset = 27; females = 38).

METHODS

Hormones assessed (plasma levels) included adrenocorticotropic hormone (ACTH), cortisol and dehydroepiandrosterone sulphate (DHEAS). Psychopathological measures included panic attacks' number during last three weeks, the Agoraphobic Cognitions and the Body Sensations Questionnaires and the Hamilton Anxiety Rating Scale.

RESULTS

Early-onset PD patients - compared to their late-onset counterparts - had longer duration of the disease. The two onset-groups demonstrated similar panic and anxiety symptoms and similar ratios of smokers/never-smokers. However, early-onset patients demonstrated significantly greater ACTH and DHEAS levels and higher (marginally significant) cortisol levels than the late-onset patients. Moreover, in the early-onset patients only, significant positive correlations emerged between ACTH levels and the severity of both panic and anxiety symptomatology.

CONCLUSIONS

These findings suggest that the two onset-groups demonstrate significant differences in the hypothalamic-pituitary-adrenal axis functioning, at least when acutely-ill.Key pointsEarly-onset panic disorder (EOPD) may differ biologically from late-onset PD (LOPD).EOPD was correlated with greater adrenocorticotropic hormone (ACTH) plasma levels.EOPD was correlated with greater dehydroepiandrosterone sulphate plasma levels.In EOPD only, ACTH levels were positively correlated with panic and anxiety symptoms.

Effects of caffeine on anxiety and panic attacks in patients with panic disorder: A systematic review and meta-analysis

BACKGROUND

Caffeine has been purported to have anxiogenic and panicogenic properties, specifically salient in patients with panic disorder (PD). However, compilations of the magnitude of the effect of caffeine on anxiety and panic attacks are lacking and potential dose-response relationships have not been examined.

OBJECTIVES

In the present systematic review and meta-analysis, we aimed to examine the acute effects of placebo-controlled caffeine challenge on occurrence of panic attacks and subjective anxiety in patients with PD and healthy controls (HC), including dose-response relationships.

METHODS

Systematic searches were performed in six databases. We included blinded placebo-controlled studies of acute caffeine challenge on panic attacks and/or subjective anxiety in adult patients with PD.

RESULTS

Of the 1893 identified articles, ten met our inclusion criteria. The 9 studies investigating panic attacks included 237 patients, of which 51.1% had a panic attack following caffeine, but none after placebo. Six of these studies compared 128 patients with 115 healthy controls (HC), finding that patients (53.9%) were more vulnerable than HC (1.7%) for panic attacks following caffeine (log RR: 3.47; 95% CI 2.06-4.87). Six studies investigated subjective anxiety in 121 patients and 111 HC following caffeine, with an overall effect indicating increased sensitivity to the anxiogenic effects of caffeine in the patient group (Hedges' g = 1.02 [95% CI: 0.09-1.96]). The restricted range of caffeine employed [400-750 mg] and few studies (3) not using 480 mg prevented any meaningful analysis of a dose-response relationship.

LIMITATIONS

Of the ten studies included, only 2 reported anxiety data for the placebo condition, precluding a proper meta-analysis comparing anxiogenic effects of caffeine and placebo. The restricted dose range used prevented assessment of dose-response relationships.

CONCLUSIONS

The results confirm that caffeine at doses roughly equivalent to 5 cups of coffee induces panic attacks in a large proportion of PD patients and highly discriminates this population from healthy adults. Caffeine also increases anxiety in PD patients as well as among healthy adults at these doses although the exact relationship between caffeine-induced anxiety and panic attacks remains uncertain. The results suggest that caffeine targets important mechanisms related to the pathophysiology of PD.

IMPLICATIONS

Future studies should employ a wider range of caffeine doses and investigate contributions of biological and psychological mechanisms underlying the anxiogenic and panicogenic effects of caffeine. In the clinic, patients with PD should be informed about the panicogenic and anxiogenic effects of caffeine, with the caveat that little is known regarding smaller doses than 480 mg. Registration. PROSPERO (www.crd.york.ac.uk/prospero) registration number CRD42019120220.

Hold your breath: Voluntary breath-holding time predicts defensive activation to approaching internal threat

Bodily disturbances, like dyspnea, elicit responses to regain homeostasis and ensure survival. However, this life-saving function can become hyperreactive, which may lead to the emergence of psychopathology. This study investigated whether maximal voluntary breath-holding time (mvBHT), a biobehavioral marker that characterizes sensitivity to respiratory stimulation, predicts defensive mobilization to cues signaling the proximity of a mild electric shock vs. a respiratory threat (shortness of breath elicited by forced breath-holding) and the opportunity to avoid threat delivery in 60 healthy participants. While the startle reflex, a measure of defensive mobilization, generally increased with the proximity of an inevitable threat, shorter breath-holding time was specifically associated with greater startle potentiation when anticipating a respiratory threat but not an electric shock. In contrast, when both threats were avoidable, the startle reflex was comparably inhibited, irrespective of mvBHT. This study suggests that mvBHT specifically predicts hypersensitive responding to an anticipated inevitable respiratory threat.

Panic attack provocation in panic disorder patients with a computer simulation

BACKGROUND

Computer simulations (CS) and virtual reality exposure are promising techniques for research and treatment of panic disorder with agoraphobia (PDA). The objective of this study was to ascertain whether a given CS was a stimulus capable of producing panic attacks (PAs), anxiety and psychophysiological changes in patients with PDA.

METHODS

Thirty PDA patients and 30 healthy subjects were recruited for this study. Subjects were exposed to a 3-min CS of a situation relevant to agoraphobic patients. Anxiety, panic symptoms, PAs, heart rate, skin conductance and respiration were recorded before, during and after the CS exposure.

RESULTS

The CS effectively induced anxiety, hyperventilation and electrodermal responses in PDA patients but not in healthy subjects. Forty percent of PDA patients had a PA while none of the control subjects had a PA. A subgroup of patients who were less sensitive to the CS than the other subgroup of PDA patients and did not present full-blown PAs still had more panic symptoms, higher anxiety levels and more respiratory irregularities than the controls.

LIMITATIONS

Low immersion and low sense of presence, lack of interaction with the environment.

CONCLUSIONS

Exposure to the CS produced effects similar to in vivo exposure, respiratory and caffeine challenges. Subsequent studies should: make direct comparisons between CS and other challenges for PDA; investigate if CS can be a tool for predicting effects of medication; determine the potential of CS as a desensitization technique for situational PAs.

Panic Disorder and Chronic Caffeine Use: A Case-control Study

Background:

Acute administration of caffeine produces panic attacks in most Panic Disorder (PD) patients, but little is known about chronic caffeine use in these patients.

Objective:

To assess caffeine use in patients with PD and to ascertain if caffeine consumption is associated with sociodemographic or clinical features.

Methods:

65 adults with PD and 66 healthy controls were included in the current study. Their caffeine intake within the previous week was quantified with a questionnaire and compared. Harmful caffeine use was defined as consumption above 400 mg/day of caffeine. We tested for correlations between caffeine intake, demographic and clinical features.

Results:

Patients consumed significantly more caffeine than controls (P < 0.001). 14% (N = 9) of the PD patients made harmful use of caffeine. The use of caffeine-containing medications was observed in 40% (N = 26) of the PD patients and 6% (N = 4) of controls. Consumption of energy drinks was observed in 11% (N = 7) of PD patients and in none of the healthy subjects. Patients reported sleeping significantly less than controls (P < 0.001). In PD patients, caffeine consumption was not correlated with the presence of panic attacks or comorbidity with depression. The use of benzodiazepines or sedative medications was not correlated with caffeine intake.

Conclusion:

High caffeine consumption in PD patients could be explained by the development of tolerance with regular use of this substance. Subtypes of sensitive and non-sensitive PD patients could also explain why some of these patients are able to tolerate high doses of caffeine.

Associations of plasma testosterone with clinical manifestations in acute panic disorder

The probable implication of testosterone in the neurobiology of anxiety disorders, and particularly panic disorder (PD), is poorly studied. We explored for potential differences concerning testosterone (T) plasma levels and the ratio testosterone/cortisol (T/C) between medication-free, consecutively-referred patients with acute exacerbation of PD comorbid with agoraphobia (PDA) (N = 40; females = 24; age = 31.4 ± 7.1 years) and healthy controls (N = 80; females = 48; matched for age). Moreover, we investigated for potential associations of T levels and T/C ratio with the severity of acute PDA psychopathology in the patients of the sample. Psychometric measures included panic attacks' number during last three weeks (PA-21days), the Agoraphobic Cognitions Questionnaire (ACQ) and the Hamilton Anxiety Rating Scale (HARS). Male patients -but not female ones- demonstrated significantly lower T levels compared to controls. Moreover, in male patients, a significant inverse association emerged between T/C ratio and PA-21days, so that lower T/C ratio is associated with significantly more panic attacks. On the contrary, female patients demonstrated significant positive associations: (a) between T levels and PDA-related pathological cognitions (ACQ); (b) between the T/C ratio and both PA-21days and anxiety symptoms' severity (HARS). The results of the study suggest that testosterone is significantly associated to the severity of clinical manifestations of acute panic disorder, although in a different fashion concerning the two genders.

Lack of specific association between panicogenic properties of caffeine and HPA-axis activation. A placebo-controlled study of caffeine challenge in patients with panic disorder

A subgroup of patients with Panic Disorder (PD) exhibits increased sensitivity to caffeine administration. However, the association between caffeine-induced panic attacks and post-caffeine hypothalamic-pituitary-adrenal (HPA)-axis activation in PD patients remains unclear. In a randomized, double-blind, cross-over experiment, 19 PD patients underwent a 400-mg caffeine-challenge and a placebo-challenge, both administered in the form of instant coffee. Plasma levels of adrenocorticotropic hormone (ACTH), cortisol and dehydroepiandrosterone sulfate (DHEAS) were assessed at both baseline and post-challenge. No patient panicked after placebo-challenge, while nine patients (47.3%) panicked after caffeine-challenge. Placebo administration did not result in any significant change in hormones' plasma levels. Overall, sample's patients demonstrated significant increases in ACTH, cortisol, and DHEAS plasma levels after caffeine administration. However, post-caffeine panickers and non-panickers did not differ with respect to the magnitude of the increases. Our results indicate that in PD patients, caffeine-induced panic attacks are not specifically associated with HPA-axis activation, as this is reflected in post-caffeine increases in ACTH, cortisol and DHEAS plasma levels, suggesting that caffeine-induced panic attacks in PD patients are not specifically mediated by the biological processes underlying fear or stress. More generally, our results add to the evidence that HPA-axis activation is not a specific characteristic of panic.

Anxiety sensitivity and expectation of arousal differentially affect the respiratory response to caffeine

RATIONALE

This study aimed to test how expectations and anxiety sensitivity influence respiratory and autonomic responses to caffeine.

OBJECTIVES

The current study investigated the effects of expected vs. unexpected caffeine ingestion in a group of persons prone to the anxiety-provoking effect of caffeine (high anxiety sensitive persons, that is, persons scoring at least one SD above the mean on the Anxiety Sensitivity Index (Peterson and Reiss 1992)) as compared to low-anxious controls.

METHODS

Autonomic arousal (heart rate, skin conductance level), respiratory responding (expired CO2, minute ventilation), and subjective report were assessed in high and low anxiety sensitive participants immediately after beverage consumption and at absorption peak (30 min post-consumption) in four separate sessions during which either coffee (expectation of caffeine) or bitter lemon soda (no expectation of caffeine) was crossed with 4 mg/kg caffeine vs. no drug.

RESULTS

High and low anxiety sensitive persons showed comparable autonomic arousal and symptom reports to caffeine which was modulated by expectation, i.e., greater for coffee. Respiratory responding (CO2 decrease, minute ventilation increase) was more accentuated when caffeine was both expected and administered in the low anxiety sensitive group but more accentuated when caffeine was unexpectedly administered in the high anxiety sensitive group. Autonomic arousal and respiratory effects were observable within a few minutes after caffeine administration and were most pronounced at maximum absorption.

CONCLUSIONS

The results highlight the modulating role of expectancies in respiratory responding to caffeine in low vs. high anxiety sensitive persons and might have important implications for the better understanding of unexpected panic attacks.

Caffeine challenge test and panic disorder: a systematic literature review

This systematic review aimed to examine the results of studies that have investigated the induction of panic attacks and/or the anxiogenic effect of the caffeine challenge test in patients with panic disorder. The literature search was performed in PubMed, Biblioteca Virtual em Saúde and the ISI Web of Knowledge. The words used for the search were caffeine, caffeine challenge test, panic disorder, panic attacks and anxiety disorder. In total, we selected eight randomized, double-blind studies where caffeine was administered orally, and none of them controlled for confounding factors in the analysis. The percentage of loss during follow-up ranged between 14.3% and 73.1%. The eight studies all showed a positive association between caffeine and anxiogenic effects and/or panic disorder.

Efeito do broncodilatador no tempo de apneia voluntária máxima em pacientes com distúrbios ventilatórios obstrutivos

OBJETIVO: Identificar o papel do broncodilatador no tempo de apneia voluntária máxima em pacientes com distúrbios ventilatórios obstrutivos (DVOs). MÉTODOS: Estudo caso-controle incluindo pacientes com DVOs e grupo controle. Foram realizadas espirometrias antes e após o uso de broncodilatador, assim como testes de apneia respiratória, utilizando-se um microprocessador eletrônico e um pneumotacógrafo como transdutor de fluxo. As curvas de fluxo respiratório foram exibidas em tempo real em um computador portátil, e os tempos de apneia voluntária inspiratória e expiratória máximos (TAVIM e TAVEM, respectivamente) foram determinados a partir do sinal adquirido. RESULTADOS: Um total de 35 pacientes com DVOs e 16 controles foram incluídos no estudo. O TAVIM sem o uso de broncodilatador foi significativamente menor no grupo DVO que no grupo controle (22,27 ± 11,81 s vs. 31,45 ± 15,73; p = 0,025), mas essa diferença não foi significativa após o uso de broncodilatador (24,94 ± 12,89 s vs. 31,67 ± 17,53 s). Os valores de TAVEM foram significativamente menores no grupo DVO que no grupo controle antes (16,88 ± 6,58 s vs. 22,09 ± 7,95 s; p = 0,017) e após o uso de broncodilatador (21,22 ± 9,37 s vs. 28,53 ± 12,46 s; p = 0,024). CONCLUSÕES: Estes resultados fornecem uma evidência adicional da utilidade clínica do teste de apneia na avaliação da função pulmonar e do papel do broncodilatador nesse teste.

Removal of caffeine from green tea by microwave-enhanced vacuum ice water extraction

In order to selectively remove caffeine from green tea, a microwave-enhanced vacuum ice water extraction (MVIE) method was proposed. The effects of MVIE variables including extraction time, microwave power, and solvent to solid radio on the removal yield of caffeine and the loss of total phenolics (TP) from green tea were investigated. The optimized conditions were as follows: solvent (mL) to solid (g) ratio was 10:1, microwave extraction time was 6 min, microwave power was 350 W and 2.5 h of vacuum ice water extraction. The removal yield of caffeine by MVIE was 87.6%, which was significantly higher than that by hot water extraction, indicating a significant improvement of removal efficiency. Moreover, the loss of TP of green tea in the proposed method was much lower than that in the hot water extraction. After decaffeination by MVIE, the removal yield of TP tea was 36.2%, and the content of TP in green tea was still higher than 170 mg g(-1). Therefore, the proposed microwave-enhanced vacuum ice water extraction was selective, more efficient for the removal of caffeine. The main phenolic compounds of green tea were also determined, and the results indicated that the contents of several catechins were almost not changed in MVIE. This study suggests that MVIE is a new and good alternative for the removal of caffeine from green tea, with a great potential for industrial application.

Cognitive enhancers for anxiety disorders

Cognitive-behavioral therapy is an effective intervention for anxiety disorders. However, a significant number of people do not respond or only show partial response even after an adequate course of the treatment. Recent research has shown that the efficacy of the intervention can be improved by the use of cognitive enhancers that augment the core learning processes of cognitive-behavior therapy. This manuscript provides a review of the current state of cognitive enhancers for the treatment of anxiety disorders.

Anxiogenic properties of a computer simulation for panic disorder with agoraphobia

BACKGROUND

There are several useful methods to induce anxiety in patients with panic disorder with agoraphobia (PDA). Our aim was to ascertain if a computer simulation (CS) could induce anxiety and physiologic alterations in PDA patients.

METHODS

10 healthy controls (HC) and 10 patients who fulfilled DSM-IV criteria for PDA were recruited for this study. The anxiety level was measured with the Subjective Units of Distress Scale (SUDS) and the Diagnostic Symptom Questionnaire (DSQ) was used to ascertain panic attack (PA) symptoms. The heart rate, skin conductance and respiration were monitored during exposure to the CS. The CS was a 3D computer animation of a short bus trip, from a first person perspective.

RESULTS

In PDA patients CS exposure increased anxiety levels, they also had higher scores in the DSQ and two of them had PA. Compared to the HC, the PDA patients had higher skin conductance level, electrodermal response magnitude, respiratory rate, tidal volume, and respiratory rate irregularities. The heart rate means were higher for PDA patients who had PA, followed by HC and PDA patients who did not have PA. There were no significant differences between the two groups regarding the sense of presence.

LIMITATIONS

The main limitations were the small sample size, and some PDA patients under medications.

CONCLUSIONS

This study indicated that CS exposure may induce anxiety, electrodermal and respiratory alterations in patients with PDA. CS exposure may be a useful tool in the research and treatment of PD patients.

Panic disorder respiratory subtype: psychopathology, laboratory challenge tests, and response to treatment

OBJECTIVE

Our objective is to summarize the new findings concerning the respiratory subtype (RS) of panic disorder (PD) since its first description.

METHODS

Two searches were made in the Institute for Scientific Information Web of Science: with the keywords "panic disorder" and "respiratory symptoms," and all articles that cited Briggs and colleagues' 1993 article "Subtyping of Panic Disorder by Symptom Profile" (Br J Psychiatry 1993;163:201-9). Altogether, 133 articles were reviewed.

RESULTS

We describe and discuss RS epidemiology, genetics, psychopathology, demographic features, clinical features, correlations with the respiratory system, traumatic suffocation history, provocative tests, and nocturnal panic. Compared to patients with the nonrespiratory subtype (non-RS), the RS patients had higher familial history of PD, lower comorbidity with depression, longer duration of illness, lower neuroticism scores, and higher scores in severity scales, such as the Panic and Agoraphobia Scale, Panic-Agoraphobia Spectrum scale and the Clinical Global Impression scale. Tests to induce panic attacks, such as those with CO(2), hyperventilation, and caffeine, produce panic attacks in a higher proportion of RS patients than non-RS patients. Differences in the subtypes' improvement with the pharmacologic treatment were found. There are also some controversial findings regarding the RS, including the age of onset of PD, and alcohol and tobacco use in RS patients.

CONCLUSIONS

Some characteristics, such as the increased sensitivity to CO(2) and the higher familial history of PD, clearly distinguish the RS from the non-RS. Nevertheless, there are also controversial findings. More studies are needed to determine the validity of the RS subtype.