Caffeine challenge in patients with panic disorder: baseline differences between those who panic and those who do not

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.

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.

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.

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.

Neuroenhancement of Exposure Therapy in Anxiety Disorders

Although exposure-based treatments and anxiolytic medications are more effective than placebo for treating anxiety disorders, there is still considerable room for further improvement. Interestingly, combining these two modalities is usually not more effective than the monotherapies. Recent translational research has identified a number of novel approaches for treating anxiety disorders using agents that serve as neuroenhancers (also known as cognitive enhancers). Several of these agents have been studied to determine their efficacy at improving treatment outcome for patients with anxiety and other psychiatric disorders. In this review, we examine d-cycloserine, yohimbine, cortisol, catecholamines, oxytocin, modafinil, and nutrients such as caffeine and amino fatty acids as potential neuroenhancers. Of these agents, d-cycloserine shows the most promise as an effective neuroenhancer for extinction learning and exposure therapy. Yet, the optimal dosing and dose timing for drug administration remains uncertain. There is partial support for cortisol, catecholamines, yohimbine and oxytocin for improving extinction learning and exposure therapy. There is less evidence to indicate that modafinil and nutrients such as caffeine and amino fatty acids are effective neuroenhancers. More research is needed to determine their long term efficacy and clinical utility of these agents.

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.

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.

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

OBJECTIVE

Breath-holding (BH) has been used as a simple probe to increase endogenous carbon dioxide (CO2). In patients with Panic Disorder (PD), lower baseline BH duration is associated with caffeine-induced panic attacks. In this paper, we assessed BH duration in PD patients in relation to panic attacks induced by caffeine intake.

METHODS

BH duration and state anxiety were assessed in 40 PD patients (12 males), both at baseline and after a 400-mg caffeine challenge test.

RESULTS

Patients panicking after caffeine administration (14 patients, 4 males) exhibited a significant reduction of their post-challenge BH duration, while no change of the BH duration was observed in non-panicking patients (26 patients, 8 males). Reduction in post-challenge BH duration was not related to higher anxiety levels--as reflected in the State-Trait Anxiety Inventory-State Form scores--independently of the occurrence of a panic attack. Panickers exhibited significantly lower baseline BH duration, compared to non-panickers.

CONCLUSIONS

Our findings indicate that in PD patients, caffeine-induced panic attacks are strongly associated with a significant reduction of BH duration at both pre- and post-challenge. Jointly, these findings suggest that in a subgroup of PD patients, sensitivity to endogenous CO2 accumulation may underlie both the lower BH durations and the caffeine-induced panic attacks. In this subgroup of PD patients, caffeine might exert its panicogenic properties through the exacerbation of patients' already pathological hypersensitivity to CO2 accumulation, as indicated by both the significant decrease of their BH duration at post-challenge and by their significantly lower baseline BH duration respectively.