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Tural U, Iosifescu DV. A systematic review and network meta-analysis of carbon dioxide provocation in psychiatric disorders. J Psychiatr Res 2021; 143:508-515. [PMID: 33250190 DOI: 10.1016/j.jpsychires.2020.11.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/09/2020] [Accepted: 11/15/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND False suffocation alarm hypothesis has been widely used to explain carbon dioxide hypersensitivity in panic disorder (PD). However, hypersensitivity to carbon dioxide has been observed in other psychiatric disorders. We explored the specificity of carbon dioxide inhalation as a panic provocation test among psychiatric disorders via network meta-analysis. METHODS A systematic literature search on PubMed, EMBASE, and PsycNET was performed to acquire the studies using the carbon dioxide provocation test in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and checklists. Odds ratios (OR) for a panic attack (PA) induced by the carbon dioxide inhalation tests were extracted from each of the original studies and were pooled using the random-effects model. RESULTS Network meta-analysis on a pool of 2181 participants from 41 studies was used to compare the efficacy of carbon dioxide provocation tests among psychiatric disorders. The network meta-analysis showed that the odds for PA in response to carbon dioxide inhalation are higher in patients with PD, premenstrual dysphoric syndrome (PMDD), and social anxiety disorder (SAD) than healthy controls (HC). The odds for PA were not significantly different among patients with generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), major depressive disorder (MDD), and healthy controls (HC). CONCLUSIONS The vulnerability to the carbon dioxide provocation test is not limited to PD. The specificity of the test for PD is questionable, as individuals suffering from PMDD and SAD are also significantly more responsive to carbon dioxide inhalation compared to HC, OCD, MDD, and GAD. There may be shared underpinning biological mechanisms between PD, PMDD, and SAD.
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Affiliation(s)
- Umit Tural
- Clinical Research Division, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA.
| | - Dan V Iosifescu
- Clinical Research Division, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Psychiatry Department, New York University School of Medicine, New York, NY 10016, USA
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2
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Leibold NK, van den Hove DLA, Weidner MT, Buchanan GF, Steinbusch HWM, Lesch KP, Schruers KRJ. Effect of serotonin transporter genotype on carbon dioxide-induced fear-related behavior in mice. J Psychopharmacol 2020; 34:1408-1417. [PMID: 33103571 PMCID: PMC7708670 DOI: 10.1177/0269881120959611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Inhaling 35% carbon dioxide induces an emotional and symptomatic state in humans closely resembling naturally occurring panic attacks, the core symptom of panic disorder. Previous research has suggested a role of the serotonin system in the individual sensitivity to carbon dioxide. In line with this, we previously showed that a variant in the SLC6A4 gene, encoding the serotonin transporter, moderates the fear response to carbon dioxide in humans. To study the etiological basis of carbon dioxide-reactivity and panic attacks in more detail, we recently established a translational mouse model. AIM The purpose of this study was to investigate whether decreased expression of the serotonin transporter affects the sensitivity to carbon dioxide. METHODS Based on our previous work, wildtype and serotonin transporter deficient (+/-, -/-) mice were monitored while being exposed to carbon dioxide-enriched air. In wildtype and serotonin transporter +/- mice, also cardio-respiration was assessed. RESULTS For most behavioral measures under air exposure, wildtype and serotonin transporter +/- mice did not differ, while serotonin transporter -/- mice showed more fear-related behavior. Carbon dioxide exposure evoked a marked increase in fear-related behaviors, independent of genotype, with the exception of time serotonin transporter -/- mice spent in the center zone of the modified open field test and freezing in the two-chamber test. On the physiological level, when inhaling carbon dioxide, the respiratory system was strongly activated and heart rate decreased independent of genotype. CONCLUSION Carbon dioxide is a robust fear-inducing stimulus. It evokes inhibitory behavioral responses such as decreased exploration and is associated with a clear respiratory profile independent of serotonin transporter genotype.
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Affiliation(s)
- Nicole K Leibold
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands,Department of Neurology, Yale School of Medicine, New Haven, USA,Nicole K Leibold, Department of Psychiatry and Neuropsychology, Maastricht University, P.O. Box 616 (Vijverdal), 6200 MD Maastricht, The Netherlands.
| | - Daniel LA van den Hove
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands,School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands,Division of Molecular Psychiatry, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany
| | - Magdalena T Weidner
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands,School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands,Division of Molecular Psychiatry, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany,Department of Psychiatry and Psychotherapy, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Gordon F Buchanan
- Department of Neurology, Yale School of Medicine, New Haven, USA,Department of Neurology, University of Iowa, Iowa City, USA,University of Iowa Graduate College, Iowa City, USA
| | - Harry WM Steinbusch
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands,School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands,Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technoglogy (DGIST), Daegu, South Korea
| | - Klaus-Peter Lesch
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands,School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands,Division of Molecular Psychiatry, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany,Laboratory of Psychiatric Neurobiology, I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Koen RJ Schruers
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands,School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands,Department of Psychology, University of Leuven, Leuven, Belgium
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Grigorova OV, Akhapkin RV, Aleksandrovsky YA. [Modern concepts of pathogenetic therapy of anxiety disorders]. Zh Nevrol Psikhiatr Im S S Korsakova 2019; 119:111-120. [PMID: 31793552 DOI: 10.17116/jnevro2019119101111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The high prevalence of anxiety disorders around the world leads to a high interest in the study of anxiety. At the moment, a lot of knowledge about the pathogenesis and therapy of anxiety disorders has been accumulated, which is well covered in modern domestic and world medical literature. It is known that many areas of the brain are involved in the modulation of anxiety, among which the amygdala is considered the key in the modulation of anxiety and fear. A large body of evidence supports the involvement of different neurotransmitter systems in the processes of anxiogenesis-anxiolysis (GABA, monoamines, glutamate, neuropeptides, neurosteroids). This article provides an analysis of methods of pharmacological impact on each of these systems, which serve to optimize the already known strategies of anxiolytic therapy.
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Affiliation(s)
- O V Grigorova
- Serbsky National Medical Research Center for Psychiatry and Narcology, Moscow, Russia
| | - R V Akhapkin
- Serbsky National Medical Research Center for Psychiatry and Narcology, Moscow, Russia
| | - Yu A Aleksandrovsky
- Serbsky National Medical Research Center for Psychiatry and Narcology, Moscow, Russia
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McMurray KM, Strawn JR, Sah R. Fluoxetine Modulates Spontaneous and Conditioned Behaviors to Carbon Dioxide (CO2) Inhalation and Alters Forebrain–Midbrain Neuronal Activation. Neuroscience 2019; 396:108-118. [DOI: 10.1016/j.neuroscience.2018.10.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 10/17/2018] [Accepted: 10/29/2018] [Indexed: 11/17/2022]
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Kellner M, Muhtz C, Nowack S, Leichsenring I, Wiedemann K, Yassouridis A. Effects of 35% carbon dioxide (CO 2) inhalation in patients with post-traumatic stress disorder (PTSD): A double-blind, randomized, placebo-controlled, cross-over trial. J Psychiatr Res 2018; 96:260-264. [PMID: 29128558 DOI: 10.1016/j.jpsychires.2017.10.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/25/2017] [Accepted: 10/27/2017] [Indexed: 11/29/2022]
Abstract
BACKGROUND In patients with post-traumatic stress disorder (PTSD) two open pilot studies about the effects of 35% carbon dioxide (CO2) exist. One shows an augmented panicogenic and anxiogenic response (Muhtz et al., 2011), the other does not (Talesnik et al. 2007). We further characterized the CO2 reactivity in PTSD using for the first time placebo-controlled and double-blind conditions. METHODS In 20 patients with PTSD we assessed panic, anxiety, dissociative and PTSD symptoms after a single vital capacity inhalation of 35% CO2 compared to a placebo gas condition in a within-participant cross-over, placebo-controlled, double-blind and randomized design. RESULTS Inhalation of 35% CO2 versus placebo provoked significantly increased panic, anxiety, dissociative and PTSD symptoms. The reaction to placebo gas was minimal. Order of inhalation, patients' sex or age did not influence the results. The panic and anxiety response under CO2 was considerably higher in the PTSD patients than in healthy controls from our previous open study. CONCLUSIONS The results corroborate that our preceding findings of an increased CO2 reactivity in patients with PTSD are not false positive due to the open design or the lack of placebo control. Replication in a larger number of PTSD patients and matched control subjects is needed. The potential role of childhood traumatisation, psychiatric comorbidity, psychotropic medication and trait dissociation in prior contradictory reports should be clarified.
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Affiliation(s)
- Michael Kellner
- University Hospital Hamburg-Eppendorf, Dept. of Psychiatry and Psychotherapy, Martinistrasse 52, 20246 Hamburg, Germany; Hospital Herford, Dept. of Psychiatry, Psychotherapy and Psychosomatics, Schwarzenmoorstraße 70, 32049 Herford, Germany.
| | - Christoph Muhtz
- University Hospital Hamburg-Eppendorf, Dept. of Psychiatry and Psychotherapy, Martinistrasse 52, 20246 Hamburg, Germany; Schön Hospital Hamburg Eilbek, Department of Psychosomatics, Dehnhaide 120, 22081 Hamburg, Germany
| | - Sven Nowack
- University Hospital Hamburg-Eppendorf, Dept. of Psychiatry and Psychotherapy, Martinistrasse 52, 20246 Hamburg, Germany
| | - Irina Leichsenring
- University Hospital Hamburg-Eppendorf, Dept. of Psychiatry and Psychotherapy, Martinistrasse 52, 20246 Hamburg, Germany
| | - Klaus Wiedemann
- University Hospital Hamburg-Eppendorf, Dept. of Psychiatry and Psychotherapy, Martinistrasse 52, 20246 Hamburg, Germany
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CO2 exposure as translational cross-species experimental model for panic. Transl Psychiatry 2016; 6:e885. [PMID: 27598969 PMCID: PMC5048202 DOI: 10.1038/tp.2016.162] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 07/10/2016] [Accepted: 07/22/2016] [Indexed: 12/13/2022] Open
Abstract
The current diagnostic criteria of the Diagnostic and Statistical Manual of Mental Disorders are being challenged by the heterogeneity and the symptom overlap of psychiatric disorders. Therefore, a framework toward a more etiology-based classification has been initiated by the US National Institute of Mental Health, the research domain criteria project. The basic neurobiology of human psychiatric disorders is often studied in rodent models. However, the differences in outcome measurements hamper the translation of knowledge. Here, we aimed to present a translational panic model by using the same stimulus and by quantitatively comparing the same outcome measurements in rodents, healthy human subjects and panic disorder patients within one large project. We measured the behavioral-emotional and bodily response to CO2 exposure in all three samples, allowing for a reliable cross-species comparison. We show that CO2 exposure causes a robust fear response in terms of behavior in mice and panic symptom ratings in healthy volunteers and panic disorder patients. To improve comparability, we next assessed the respiratory and cardiovascular response to CO2, demonstrating corresponding respiratory and cardiovascular effects across both species. This project bridges the gap between basic and human research to improve the translation of knowledge between these disciplines. This will allow significant progress in unraveling the etiological basis of panic disorder and will be highly beneficial for refining the diagnostic categories as well as treatment strategies.
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Lifestyle Behaviours Add to the Armoury of Treatment Options for Panic Disorder: An Evidence-Based Reasoning. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:7017-43. [PMID: 26095868 PMCID: PMC4483746 DOI: 10.3390/ijerph120607017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 06/11/2015] [Accepted: 06/12/2015] [Indexed: 11/16/2022]
Abstract
This article presents an evidence-based reasoning, focusing on evidence of an Occupational Therapy input to lifestyle behaviour influences on panic disorder that also provides potentially broader application across other mental health problems (MHP). The article begins from the premise that we are all different. It then follows through a sequence of questions, examining incrementally how MHPs are experienced and classified. It analyses the impact of individual sensitivity at different levels of analysis, from genetic and epigenetic individuality, through neurotransmitter and body system sensitivity. Examples are given demonstrating the evidence base behind the logical sequence of investigation. The paper considers the evidence of how everyday routine lifestyle behaviour impacts on occupational function at all levels, and how these behaviours link to individual sensitivity to influence the level of exposure required to elicit symptomatic responses. Occupational Therapists can help patients by adequately assessing individual sensitivity, and through promoting understanding and a sense of control over their own symptoms. It concludes that present clinical guidelines should be expanded to incorporate knowledge of individual sensitivities to environmental exposures and lifestyle behaviours at an early stage.
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The brain acid–base homeostasis and serotonin: A perspective on the use of carbon dioxide as human and rodent experimental model of panic. Prog Neurobiol 2015; 129:58-78. [DOI: 10.1016/j.pneurobio.2015.04.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 04/16/2015] [Accepted: 04/20/2015] [Indexed: 12/14/2022]
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Knuts I, Esquivel G, Kenis G, Overbeek T, Leibold N, Goossens L, Schruers K. Therapygenetics: 5-HTTLPR genotype predicts the response to exposure therapy for agoraphobia. Eur Neuropsychopharmacol 2014; 24:1222-8. [PMID: 24906789 DOI: 10.1016/j.euroneuro.2014.05.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 04/27/2014] [Accepted: 05/09/2014] [Indexed: 01/09/2023]
Abstract
This study was intended to assess the extent to which the low-expression allele of the serotonin transporter gene promoter predicts better response to exposure-based behavior therapy in patients with panic disorder with agoraphobia (PDA). Ninety-nine patients with PDA underwent a 1-week in vivo exposure-based behavior therapy program and provided saliva samples to extract genomic DNA and classify individuals according to four allelic forms (SA, SG, LA, LG) of the 5-HTT-linked polymorphic region (5-HTTLPR). We determined whether the 5-HTTLPR genotype predicted change in avoidance behavior in PDA following treatment. After controlling for pre-treatment avoidance behavior, the 5-HTTLPR low-expression genotypes showed a more favorable response to exposure therapy two weeks following treatment, compared to the other patients. This study suggests a genetic contribution to treatment outcome following behavior therapy and implicates the serotonergic system in response to exposure-based treatments in PDA.
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Affiliation(s)
- Inge Knuts
- School for Mental Health en Neuroscience, Maastricht University and Mondriaan, Vijverdalseweg 1, gebouw Concorde, 6226 NB Maastricht, The Netherlands.
| | - Gabriel Esquivel
- School for Mental Health en Neuroscience, Maastricht University,Maastricht, The Netherlands
| | - Gunter Kenis
- School for Mental Health en Neuroscience, Maastricht University,Maastricht, The Netherlands
| | - Thea Overbeek
- School for Mental Health en Neuroscience, Maastricht University,Maastricht, The Netherlands
| | - Nicole Leibold
- School for Mental Health en Neuroscience, Maastricht University,Maastricht, The Netherlands
| | - Lies Goossens
- School for Mental Health en Neuroscience, Maastricht University,Maastricht, The Netherlands
| | - Koen Schruers
- School for Mental Health en Neuroscience, Maastricht University,Maastricht, The Netherlands
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Tõru I, Maron E, Raag M, Vasar V, Nutt DJ, Shlik J. The effect of 6-week treatment with escitalopram on CCK-4 challenge: a placebo-controlled study in CCK-4-sensitive healthy volunteers. Eur Neuropsychopharmacol 2013; 23:645-52. [PMID: 22939006 DOI: 10.1016/j.euroneuro.2012.08.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Revised: 07/16/2012] [Accepted: 08/07/2012] [Indexed: 10/27/2022]
Abstract
Cholecystokinin-tetrapeptide (CCK-4)-induced panic attacks are reportedly attenuated by effective treatment with antipanic antidepressants in patients with panic disorder, but in healthy volunteers such effects are not well studied. The aim of this study was to assess the effect of 6-week treatment with an SSRI escitalopram on CCK-4-induced symptoms in healthy volunteers, who previously responded with a panic attack to CCK-4 challenge. A total of 18 healthy subjects (10 males and eight females, mean age 22.5 ± 5.8) received a 6-week treatment with escitalopram (10 mg/day) and placebo followed by CCK-4 challenge (50 μg) in a double-blind crossover design. The panic rate was 67% after treatment with escitalopram and 56% after treatment with placebo (p = 0.7). Thus, the results showed a significant reduction in CCK-4-induced panic rates without significant differences between escitalopram and placebo conditions. There were no significant effects of either treatment on any other variable of anxiety or cardiovascular indices. Secondary analysis showed no effect of gender or 5-HTTLPR polymorphism on response to CCK-4 challenge. This study demonstrated that in contrast to the findings in patients with panic disorder, in CCK-4-sensitive healthy volunteers the treatment with an antipanic SSRI did not cause a reduction of CCK-4-induced panic attacks beyond the effect of placebo. The mechanisms behind this discrepancy and the reasons of the decrease in sensitivity to CCK-4 challenge on repeated administration remain to be clarified in future studies.
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Affiliation(s)
- Innar Tõru
- Department of Psychiatry, University of Tartu, Tartu, Estonia.
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Verschoor E, Markus CR. Physiological and affective reactivity to a 35% CO₂ inhalation challenge in individuals differing in the 5-HTTLPR genotype and trait neuroticism. Eur Neuropsychopharmacol 2012; 22:546-54. [PMID: 22209359 DOI: 10.1016/j.euroneuro.2011.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 11/01/2011] [Accepted: 12/02/2011] [Indexed: 11/25/2022]
Abstract
The inhalation of 35% carbon dioxide (CO₂) results in an acute stress response in healthy individuals and may accordingly provide a good paradigm to examine potential vulnerability factors for stress reactivity and stress-related psychopathology. It has been proposed that CO₂ reactivity is moderated by genetic (5-HTTLPR) and personality (neuroticism) factors, yet no experimental study has investigated their effects on CO₂ reactivity simultaneously. The current study examined the singular and interactive effects of the 5-HTTLPR genotype and neuroticism in predicting the affective and physiological response to a 35% CO₂ challenge in a healthy sample of male and female students. From a large group of 771 students, 48 carriers of the low/low expressing allele (S/S, S/Lg, Lg/Lg) and 48 carriers of the high/high expressing allele (La/La) with the lowest and the highest neuroticism scores (77 females, 19 males; mean age ± SD: 20.6 ± 2 years) were selected and underwent a 35% CO₂ inhalation. Visual analogue scales for anxiety and discomfort and the Panic Symptom List were used to assess affective symptomatology, while salivary samples and heart rate were assessed to establish the physiological response. A typical pattern of responses to CO₂ was observed, characterised by increases in anxiogenic symptoms and physical panic symptomatology and a reduction in heart rate; however, no effect on salivary cortisol concentration was observed. Additionally, the CO₂ reactivity did not differ between groups divided by the 5-HTTLPR genotype or neuroticism. Findings of the current study do not support a role for singular or interactive effects of the 5-HTTLPR genotype and trait neuroticism on affective and physiological reactivity to a 35% CO₂ inhalation procedure.
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Affiliation(s)
- Ellen Verschoor
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands
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Freire RC, Hallak JE, Crippa JA, Nardi AE. New treatment options for panic disorder: clinical trials from 2000 to 2010. Expert Opin Pharmacother 2011; 12:1419-28. [DOI: 10.1517/14656566.2011.562200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Fornaro M. Agomelatine in the treatment of panic disorder. Prog Neuropsychopharmacol Biol Psychiatry 2011; 35:286-7. [PMID: 20933043 DOI: 10.1016/j.pnpbp.2010.09.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 09/27/2010] [Accepted: 09/28/2010] [Indexed: 12/26/2022]
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Colasanti A, Esquivel G, den Boer E, Horlings A, Dandachi A, Oostwegel JL, van Donkelaar EL, Griez EJ, Schruers K. Effects of tryptophan depletion and tryptophan loading on the affective response to high-dose CO2 challenge in healthy volunteers. Psychopharmacology (Berl) 2011; 215:739-48. [PMID: 21336580 PMCID: PMC3102203 DOI: 10.1007/s00213-011-2177-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 01/07/2011] [Indexed: 12/20/2022]
Abstract
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. Each subject received ATD, ATL, and a balanced condition (BAL) in separate days, and a double-breath 35% CO(2) inhalation 4.5 h after treatment. Tryptophan (Trp) manipulations were obtained adding 0 g (ATD), 1.21 g (BAL), and 5.15 g (ATL) of l-tryptophan to a protein mixture lacking Trp. Assessments consisted of a visual analogue scale for affect (VAAS) and panic symptom list. A separate analysis on a sample of 55 subjects with a separate-group design has also been performed to study the relationship between plasma amino acid levels and subjective response to CO(2). RESULTS CO(2)-induced subjective distress and breathlessness were significantly lower after ATD compared to BAL and ATL (p < 0.05). In the separate-group analysis, ΔVAAS scores were positively correlated to the ratio Trp:ΣLNAA after treatment (r = 0.39; p < 0.05). CONCLUSIONS The present results are in line with preclinical data indicating a role for the serotonergic system in promoting the aversive respiratory sensations to hypercapnic stimuli (Richerson, Nat Rev Neurosci 5(6):449-461, 2004). The differences observed in our study, compared to previous findings in PD patients, might depend on an altered serotonergic modulatory function in patients compared to healthy subjects.
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Affiliation(s)
- Alessandro Colasanti
- Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands.
| | - Gabriel Esquivel
- Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Erik den Boer
- Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Annerieke Horlings
- Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Abdul Dandachi
- Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | | | - Eva L. van Donkelaar
- Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Eric J. Griez
- Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Koen Schruers
- Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
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Mochcovitch MD, Nardi AE. Selective serotonin-reuptake inhibitors in the treatment of panic disorder: a systematic review of placebo-controlled studies. Expert Rev Neurother 2010; 10:1285-93. [PMID: 20662754 DOI: 10.1586/ern.10.110] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The selective serotonin-reuptake inhibitors are widely used in clinical practice in the treatment of panic disorder (PD). This article undertakes an up-to-date, systematic review of the published double-blind, placebo-controlled, randomized, short-term studies with currently available selective serotonin-reuptake inhibitors in the treatment of PD. Sertraline, paroxetine, citalopram, escitalopram, fluoxetine and fluvoxamine have all been proven to be superior to pill-placebo, although the placebo effect has been shown to be extremely important in patients with PD. The authors also explore the anxiolytic mechanism of action of this antidepressant drug class and the preclinical studies that are being developed to clarify the etiopathogenic mechanisms of PD and, more precisely, the role of the serotoninergic system in this pathogenesis. These steps are considered fundamental for the improvement of pharmacological treatment of PD.
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Affiliation(s)
- Marina Dyskant Mochcovitch
- Federal University of Rio de Janeiro, National Institute for Translational Medicine, Rio de Janeiro, Brazil.
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Lim LW, Blokland A, Tan S, Vlamings R, Sesia T, Aziz-Mohammadi M, Visser-Vandewalle V, Steinbusch HW, Schruers K, Temel Y. Attenuation of fear-like response by escitalopram treatment after electrical stimulation of the midbrain dorsolateral periaqueductal gray. Exp Neurol 2010; 226:293-300. [DOI: 10.1016/j.expneurol.2010.08.035] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 08/26/2010] [Accepted: 08/30/2010] [Indexed: 11/26/2022]
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Knuts IJE, Cosci F, Esquivel G, Goossens L, van Duinen M, Bareman M, Overbeek T, Griez EJL, Schruers KRJ. Cigarette smoking and 35% CO(2) induced panic in panic disorder patients. J Affect Disord 2010; 124:215-8. [PMID: 19896718 DOI: 10.1016/j.jad.2009.10.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 10/09/2009] [Accepted: 10/09/2009] [Indexed: 11/15/2022]
Abstract
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. The present study seeks to examine whether cigarette smoking has an influence on laboratory elicited panic in PD patients. METHODS In total 92 subjects (46 smokers and 46 non-smokers) with PD, according to the DSM-IV criteria, were compared. All subjects received a baseline clinical assessment and underwent a 35% CO(2) challenge. Response to the challenge was evaluated via the Panic Symptom List and the Visual Analogue Fear Scale. RESULTS The two samples did not differ on baseline anxiety level. Smokers had a significantly higher increase in panic symptoms in response to the challenge compared to non-smokers (p=0.04). LIMITATIONS This type of study does not provide information concerning the underlying mechanisms of the link between smoking and panic. Study limitations include lack of formal assessment of personality and of inter-rater reliability. CONCLUSIONS The present findings are consistent with the idea that smoking facilitates panic in PD subjects. This may have clinical implications, as quitting smoking could become one of the relevant steps in the treatment of PD patients.
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Affiliation(s)
- Inge J E Knuts
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands.
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Papadopoulos A, Rich A, Nutt DJ, Bailey JE. The effects of single dose anxiolytic medication on the CO2 models of anxiety: differentiation of subjective and objective measures. J Psychopharmacol 2010; 24:649-56. [PMID: 18832434 DOI: 10.1177/0269881108097716] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This was a double blind, placebo-controlled, 4-way cross-over study in 12 healthy volunteer subjects of the acute effects of three drugs each of which are used in the clinic to treat some forms of anxiety: propranolol 40 mg, hydroxyzine 25 mg, flupentixol 0.5 mg and placebo. Each test session consisted of inhalation of air for 20 min, 10-min rest, inhalation of CO2 7.5% for 20 min, 10-min rest, followed by a single vital capacity inhalation of 35% CO2. The CO2 7.5% was administered at peak drug effect. Subjective effects were measured using Visual Analogue Scales (VAS), the Panic Symptom Inventory and the Generalised Anxiety Disorder Assessment inventory. Twelve subjects participated (eight men), with a mean age of 25.9 years. The expected subjective effects of CO2 were seen and these were significantly different from effects of peak air. However, there were no statistically significant differences between the drugs or between drugs and placebo, indeed there was a trend for some VAS anxiety scores to be higher than placebo in the drug groups. There were some significant differences in cardiovascular responses to CO2, with propranolol significantly decreasing heart rate and flupentixol increasing blood pressure when compared with placebo. The lack of subjective anxiolytic actions of the three drugs contrasts with our previous findings with acute benzodiazepines and chronic selective serotonin reuptake inhibitor administration. It may be that prolonged treatment with these agents would be required to show anxiolytic effects, although it may also be that their efficacy is insufficient to be demonstrated in this model. The lack of anxiolytic actions of propranolol, despite a significant reduction in heart rate, is a further support for a central action of CO2 to produce anxiety.
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Affiliation(s)
- A Papadopoulos
- Psychopharmacology Unit, University of Bristol, Bristol, UK
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19
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Abstract
Understanding the neurochemistry of anxiety is of fundamental importance in the development and use of novel anxiolytics. Through measuring peripheral markers of brain biochemistry, direct pharmacological challenges and brain neuroimaging techniques our understanding of this field has increased substantially in the past few decades. We review the four most studied neurotransmitter systems with respect to in anxiety disorders: gamma amino-butyric acid, serotonin, noradrenaline and dopamine. We have focussed upon clinical studies to highlight the current techniques used to determine brain neurochemistry in vivo. Future research in this field will greatly benefit from recent advances in neuroimaging techniques and the discovery of novel ligands targeting specific receptors.
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Affiliation(s)
- C Durant
- Psychopharmacology Unit, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, UK.
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20
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Kellner M, Muhtz C, Demiralay C, Husemann J, Koelsch W, Yassouridis A, Wiedemann K. The selective serotonin re-uptake inhibitor escitalopram modulates the panic response to cholecystokinin tetrapeptide in healthy men depending on 5-HTTLPR genotype. J Psychiatr Res 2009; 43:642-8. [PMID: 18930474 DOI: 10.1016/j.jpsychires.2008.09.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Revised: 08/11/2008] [Accepted: 09/03/2008] [Indexed: 11/27/2022]
Abstract
Selective serotonin re-uptake inhibitors, such as escitalopram, are currently the treatment of choice for patients with panic disorder. The panic response to intravenous cholecystokinin tetrapeptide, a potentially useful paradigm for volunteer translational studies, has so far not been investigated in healthy man after respective pre-treatment. In a double-blind, placebo-controlled, randomized, within subject cross-over design 30 healthy young men, 15 each with the long/long or short/short genotype for the serotonin transporter linked polymorphic region, were pre-treated with 10mg/d of escitalopram orally for six weeks and then challenged with 50 microg of cholecystokinin tetrapeptide. The primary outcome measure was the increase of Acute Panic Inventory ratings by cholecystokinin tetrapeptide. The increase of anxiety, tension and stress hormone secretion were secondary outcome measures. A significant treatment by genotype effect on the increases of Acute Panic Inventory ratings emerged. Panic induced by cholecystokinin tetrapeptide was significantly more pronounced in the short/short genotype subjects under escitalopram vs. placebo pre-treatment. With the exception of significantly elevated serum prolactin after escitalopram, no effects in the secondary outcome measures were detected. Contrary to our expectation, no inhibitory effect of escitalopram upon panic symptoms elicited by choleystokinin tetrapeptide could be demonstrated in healthy men. These findings do not support the potential usefulness of this panic model for proof-of-concept studies. The biological underpinnings of the increased panic symptoms after escitalopram in our volunteers with short/short genotype need further research.
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Affiliation(s)
- Michael Kellner
- University Hospital Hamburg-Eppendorf, Department of Psychiatry, Martinistrasse 52, D-20246 Hamburg, Germany.
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Bailey JE, Kendrick A, Diaper A, Potokar JP, Nutt DJ. A validation of the 7.5% CO2 model of GAD using paroxetine and lorazepam in healthy volunteers. J Psychopharmacol 2007; 21:42-9. [PMID: 16533865 DOI: 10.1177/0269881106063889] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The inhalation of 7.5% carbon dioxide (CO2) in healthy subjects produces an increase in blood pressure and heart rate, and increased feelings of anxiety, fear and tension (Bailey et al. 2005). As this state is similar to that of general anxiety rather than panic, we further validated this by examining the effects of anxiolytic medication. Two separate studies in healthy volunteers are described; study one is a double-blind, placebo-controlled study of a single dose of 2 mg lorazepam and study two describes the effects of 21 days of treatment with paroxetine. Gas challenges were air and 7.5% CO2 inhaled for 20 minutes, delivered on day 0 (before treatment) and day 21 (after treatment) in the paroxetine study. Subjective effects were measured using visual analogue scales and questionnaires. When compared with placebo, lorazepam 2 mg significantly reduced peak CO2-induced subjective fear, feelings of wanting to leave, tension and worry. In the paroxetine study, when compared with day 0, day 21 showed a significantly attenuated peak CO2-induced nervousness and a trend for reduced ratings of anxiety, fear, feel like leaving, tense and worried. In these studies we have shown that this CO2 model of anxiety is sensitive to lorazepam and to a lesser extent paroxetine. This gives support to its utility as an experimental model of general anxiety disorder in healthy volunteers.
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Affiliation(s)
- Jayne E Bailey
- Psychopharmacology Unit, Department of Respiratory Medicine, University of Bristol, United Bristol Healthcare Trust, UK.
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Abstract
The essential role of serotonin (5-hydroxytryptamine (5-HT)) system in the neurobiology and pharmacotherapy of panic disorder (PD) continues to be a topic of intensive interdisciplinary research. Interest in the involvement of 5-HT in PD has been fuelled by clinical studies demonstrating that medications increasing the synaptic availability of 5-HT, such as selective 5-HT re-uptake inhibitors, are effective in the treatment of PD. Rival theories of 5-HT deficiency vs excess have attempted to explain the impact of 5-HT function in PD. In the past decade, knowledge of the role of 5-HT in the neurobiology of PD has expanded dramatically due to much new research including experimental, treatment, brain-imaging, and genetic studies. The current review attempts to summarize the new data and their implications. The challenge and treatment studies generally confirm the specific inhibitory influence of 5-HT on panicogenesis. The brain-imaging studies in PD patients demonstrate functional and clinically relevant alterations in various elements of 5-HT system affecting the neurocircuitry of panic. The findings of genetic association studies suggest that certain 5-HT-related genes may contribute to the susceptibility to PD; however, these data are rather limited and inconsistent. It appears that, even if not the primary etiological factor in PD, the 5-HT function conveys important vulnerability, as well as adaptive factors. A better understanding of these processes may be critical in achieving progress in the treatment of patients suffering from PD.
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Affiliation(s)
- Eduard Maron
- Department of Psychiatry, University of Tartu, Tartu, Tartumaa, Estonia.
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Poma SZ, Milleri S, Squassante L, Nucci G, Bani M, Perini GI, Merlo-Pich E. Characterization of a 7% carbon dioxide (CO2) inhalation paradigm to evoke anxiety symptoms in healthy subjects. J Psychopharmacol 2005; 19:494-503. [PMID: 16166187 DOI: 10.1177/0269881105056533] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The present study is aimed at characterizing the carbon dioxide (CO2) procedure in healthy subjects to achieve reliable provocation of anxiety symptoms. Thirty healthy subjects inhaled in single-blind both compressed air and 7% CO2 mixture. Panic Symptom List (PSLIII-R), Visual Analogue Scale-Anxiety (VAS-A), State Anxiety Inventory (STAI-Y/1), respiratory parameters and skin conductance were measured. 'Responders' were classified depending on PSLIII-R scores after CO2. Twelve out of the 21 'responders' performed a second test to assess test-retest repeatability. In 21 subjects Delta%VAS-A (45.4 +/- 32.1) and PSLIII-R (pre-test 2.3 +/-2.1, post-test 17.5 +/- 8.2) but not STAI-Y/1, significantly increased during CO2 inhalation. Respiratory Rate, Minute Volume, end-Tidal CO2 and skin conductance rose in 'responders'. Repeatability was studied with Bland-Altman plots, revealing mean difference between tests close to 0 for both Delta%VAS-A and PSLIII-R. Among physiologic parameters, end-Tidal CO2 and Respiratory Rate showed good repeatability, with a within-subject CV of 9.2% and 6%, respectively. The challenge produced measurable response in healthy subjects. Good test-retest repeatability was observed in 'responders'. These data indicate that the test can be suitable for testing putative anti-panic or anxiolytic drugs in clinical studies using a within subject, crossover design.
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Affiliation(s)
- Stefano Zanone Poma
- Psychiatry Centre of Excellence for Drug Discovery, Medical Research Centre, GlaxoSmithKline, Verona, Italy.
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