Panic disorder: the place of benzodiazepines and selective serotonin reuptake inhibitors

An update on the treatment of premature ejaculation: A systematic review

To analyse the current therapeutic options for patients with premature ejaculation (PE) and highlight their mechanism(s) of action, effectiveness, advantages and limitations. A literature search was conducted using the PubMed database searching for articles exploring different PE treatment modalities. A Preferred Reporting Items for Systemic Reviews and Meta-Analyses (PRISMA) approach was used to report the results of the literature search. A total of 149 articles were included in this review. The currently available treatment methods for PE include behavioural therapy, local anaesthetics, tricyclic antidepressants, selective serotonin reuptake inhibitors, and selective phosphodiesterase inhibitors. Most PE treatments are either experimental or used off-label. New treatments are certainly warranted to overcome this exasperating sexual dysfunction.

Abbreviations: AIPE: Arabic Index of Premature Ejaculation; CNS: central nervous system; CYP: cytochrome P450; ED: erectile dysfunction; FDA: United States Food and Drug Administration; H1: histamine receptors; 5-HT: 5-hydroxytryptamine; IELT: The intravaginal ejaculation latency time; IPE: Index of Premature Ejaculation; M1: muscarinic receptors; OCD: obsessive–compulsive disorder; PDE5: phosphodiesterase type 5; PE: premature ejaculation; PEP: Premature Ejaculation Profile; PRO: patient-reported outcome; RCT: randomised controlled trial; SS: Severance Secret (cream); SSRIs: selective serotonin reuptake inhibitors; TCAs: tricyclic antidepressants

Comparative efficacy and acceptability of antidepressants and benzodiazepines for the treatment of panic disorder: A systematic review and network meta-analysis

OBJECTIVE

This systematic review aims to assess the efficacy and acceptability of the different types of antidepressants and benzodiazepines for the treatment of panic disorder (PD) in adult patients.

METHODS

PubMed, Web of Science, EMBASE, MEDLINE, the Cochrane Library, and ClinicalTrials.gov were searched for randomized controlled trials (RCTs) published between 1995 and 2020 on the use of antidepressants and benzodiazepines for the treatment of PD. A systematic review and network meta-analysis were performed.

RESULTS

42 RCTs were included in the network meta-analysis, with a comparison of 11 interventions.Escitalopram (odds ratios OR 1.52, 95 % credible interval CI 1.09-2.10), venlafaxine (OR 1.33, 95 % CI 1.16-1.51) and benzodiazepines (OR 1.50, 95 % CI 1.29-1.75) had greater efficacy and acceptability than the placebo. Imipramine(OR 1.43, 95 % CI 1.15-1.79) was also demonstrated to be efficacious and tolerated but the results were restricted to small sample size. Moreover, paroxetine, sertraline, fluoxetine, citalopram and clomipramine (OR 1.37, 1.36, 1.45, 1.33 and 1.36, respectively) were more efficacious, although the acceptability of paroxetine and sertraline were significantly less tolerated than benzodiazepines. Notably, the efficacy of reboxetine and fluvoxamine were merely as equal as that of the placebo.

OUTCOMES

This is the first systematic review of antidepressants and benzodiazepines for the treatment of PD to use a network analysis. Escitalopram and venlafaxine as well as benzodiazepines may be effective choices as treatments for PD with relatively good acceptability, which still needs to be confirmed byhigh-quality RCTs.

The Risk of Acute Pancreatitis and Selective Serotonin Reuptake Inhibitors Use: A Meta-Analysis of Case-Control Studies

Background/Objective:

Some case series and case report have shown the association between the risk of acute pancreatitis and use of selective serotonin reuptake inhibitors. The results of systematic studies were not consistent.

Methods:

A meta-analysis was performed to investigate the risk of acute pancreatitis associated with use of selective serotonin reuptake inhibitors.

Results:

There was no statistical association between the risk of acute pancreatitis and selective serotonin reuptake inhibitors use (odds ratio: 1.19, 95% confidence interval: 0.93-1.51).

Conclusions:

Despite reaching no statistical significance, the possibility of the association between the risk of acute pancreatitis and selective serotonin reuptake inhibitors use cannot be totally excluded.

Pharmacotherapy of Lower Respiratory Tract Infections in Elderly-Focused on Antibiotics

Lower respiratory tract infections (LRTIs) refer to the inflammation of the trachea, bronchi, bronchioles, and lung tissue. Old people have an increased risk of developing LRTIs compared to young adults. The prevalence of LRTIs in the elderly population is not only related to underlying diseases and aging itself, but also to a variety of clinical issues, such as history of hospitalization, previous antibacterial therapy, mechanical ventilation, antibiotic resistance. These factors mentioned above have led to an increase in the prevalence and mortality of LRTIs in the elderly, and new medical strategies targeting LRTIs in this population are urgently needed. After a systematic review of the current randomized controlled trials and related studies, we recommend novel pharmacotherapies that demonstrate advantages for the management of LRTIs in people over the age of 65. We also briefly reviewed current medications for respiratory communicable diseases in the elderly. Various sources of information were used to ensure all relevant studies were included. We searched Pubmed, MEDLINE (OvidSP), EMBASE (OvidSP), and ClinicalTrials.gov. Strengths and limitations of these drugs were evaluated based on whether they have novelty of mechanism, favorable pharmacokinetic/pharmacodynamic profiles, avoidance of interactions and intolerance, simplicity of dosing, and their ability to cope with challenges which was mainly evaluated by the primary and secondary endpoints. The purpose of this review is to recommend the most promising antibiotics for treatment of LRTIs in the elderly (both in hospital and in the outpatient setting) based on the existing results of clinical studies with the novel antibiotics, and to briefly review current medications for respiratory communicable diseases in the elderly, aiming to a better management of LRTIs in clinical practice.

The effect of 6-week treatment with escitalopram on CCK-4 challenge: a placebo-controlled study in CCK-4-sensitive healthy volunteers

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.

Medication dependence and anxiety

Anxiety disorders are common and costly psychiatric illnesses. Pharmacological treatment was enhanced with the introduction of benzodiazepines, which proved safer and more effective than older drugs. The risk of dependence, however, has made clinicians reluctant to use these medications. In fact, few patients appear to develop significant difficulties with these drugs, given how widely they are used. Careful planning for discontinuation of therapy is important. In addition, for some individuals, there appears to be a complex and as yet unelucidaied relationship between dependence on drugs or alcohol and anxiety. The newer antidepressants offer efficacy without abuse or dependence liability, but are expensive and have side effects that are intolerable for some patients. Pharmacological therapy for anxiety should be prescribed and managed so as to minimize any existing risk, while aiming to restore the patient to wellness in terms of symptoms and function.

Efficacy of chronic antidepressant treatments in a new model of extreme anxiety in rats

Animal models of anxious disorders found in humans, such as panic disorder and posttraumatic stress disorder, usually include spontaneous and conditioned fear that triggers escape and avoidance behaviors. The development of a panic disorder model with a learned component should increase knowledge of mechanisms involved in anxiety disorders. In our ethological model of extreme anxiety in the rat, forced apnea was combined with cold water vaporization in an inescapable situation. Based on the reactions of vehicle controls, behaviors involved in paroxysmic fear were passive (freezing) and active (jumping) reactions. Our results show that subchronic fluoxetine (5 mg/kg, IP, 21 days) and imipramine (10 mg/kg, IP, 14 days) administration alleviated freezing and jumping behaviors, whereas acute fluoxetine (1 mg/kg, IP) provoked opposite effects. Acute low dose of diazepam (1 mg/kg, IP) was not effective, whereas the higher dose of 3 mg/kg, IP, and clonazepam (1 mg/kg, IP) only had an effect on jumping. Paroxysmic fear generated in this experimental condition may therefore mimic the symptomatology observed in patients with anxiety disorders.

Selective serotonin-reuptake inhibitors in the treatment of panic disorder: a systematic review of placebo-controlled studies

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.

Examining face and construct validity of a noninvasive model of panic disorder in Lister-hooded rats

RATIONALE

Increasing evidence suggests that defensive escape behavior in Lister-hooded (LH) rats induced by ultrasound application may be an animal model of panic disorder.

OBJECTIVE

The objectives of this study were to further explore the face and construct validity of ultrasound-induced escape behavior by characterizing the autonomic and neuroendocrine response to ultrasound, and to examine the underlying neuronal structures by comparing the effects of the anxiolytic with panicolytic properties, diazepam, with a preclinical anxiolytic without panicolytic-like activity, the NOP agonist Ro 64-6198.

MATERIALS AND METHODS

LH rats were implanted with telemetry transmitters to monitor heart rate and core body temperature before, during, and after ultrasound application. Blood samples were taken after ultrasound application for corticosterone analysis. Ultrasound-induced c-Fos expression was measured in different periaqueductal gray (PAG) and amygdala subregions after treatment with diazepam or Ro 64-6198.

RESULTS

Ultrasound application increased heart rate and body temperature, but did not alter plasma corticosterone levels. Ultrasound application increased c-Fos expression in the dorsal and dorsolateral PAG (dPAG, dlPAG) and amygdaloid subregions. Diazepam, but not Ro 64-6198, reduced c-Fos expression in the dPAG/dlPAG, while Ro 64-6198, but not diazepam, reduced c-Fos expression in the central amygdala.

CONCLUSIONS

Similar to human panic attacks, ultrasound application to LH rats activated the autonomic, but not the neuroendocrine, stress system. Also, like in humans, the current data confirm and extend that the dPAG/dlPAG plays a key role in ultrasound-induced escape behavior. These observations suggest that ultrasound-induced escape behaviors in LH rats have face and construct validity for panic disorders.

Alprazolam potentiates the antiaversive effect induced by the activation of 5-HT(1A) and 5-HT (2A) receptors in the rat dorsal periaqueductal gray

RATIONALE

Serotonin in the dorsal periaqueductal gray (DPAG) through the activation of 5-HT(1A) and 5-HT(2A) receptors inhibits escape, a defensive behavior associated with panic attacks. Long-term treatment with antipanic drugs that nonselectively or selectively blocks the reuptake of serotonin (e.g., imipramine and fluoxetine, respectively) enhances the inhibitory effect on escape caused by intra-DPAG injection of 5-HT(1A) and 5-HT(2A) receptor agonists. It has been proposed that these compounds exert their effect on panic by facilitating 5-HT-mediated neurotransmission in the DPAG.

OBJECTIVES

The objective of this study was to investigate whether facilitation of 5-HT neurotransmission in the DPAG is also observed after treatment with alprazolam, a pharmacologically distinct antipanic drug that acts primarily as a high potency benzodiazepine receptor agonist.

MATERIALS AND METHODS

Male Wistar rats, subchronically (3-6 days) or chronically (14-17 days) treated with alprazolam (2 and 4 mg/kg, i.p.) were intra-DPAG injected with (+/-)-8-hydroxy-2-(di-n-propylamino)tetralin hydrobromide (8-OH-DPAT), (+/-)-1-(2,5-dimethoxy-4-iodophenyl) piperazine dihydrochloride (DOI), and midazolam, respectively, 5-HT(1A), 5-HT(2A/2C), and benzodiazepine receptor agonists. The intensity of electrical current that needed to be applied to the DPAG to evoke escape behavior was measured before and after the microinjection of these agonists.

RESULTS

Intra-DPAG injection of the 5-HT agonists and midazolam increased the escape threshold in all groups of animals tested, indicating a panicolytic-like effect. The inhibitory effect of 8-OH-DPAT and DOI, but not midazolam, was significantly higher in animals receiving long-, but not short-term treatment with alprazolam.

CONCLUSIONS

Alprazolam as antidepressants compounds facilitates 5-HT(1A)- and 5-HT(2A)-receptor-mediated neurotransmission in the DPAG, implicating this effect in the mode of action of different classes of antipanic drugs.

Social isolation in prairie voles induces behaviors relevant to negative affect: toward the development of a rodent model focused on co-occurring depression and anxiety

Recent evidence suggests substantial overlap between mood and anxiety disorders, both in clinical presentation and associated features. A theoretical framework to account for this overlap focuses on negative affectivity, defined as the disposition to experience negative emotional states, including fear, sadness, and guilt. This model has been successful in explaining the co-occurrence of depressive and anxiety disorders in humans. As a next step, development of an animal model focused on both depression- and anxiety-relevant behaviors may advance understanding of depression-anxiety symptom overlap, relations of these disorders with associated medical conditions and responses to treatment. This study was designed to investigate inducible and quantifiable depression- and anxiety-like behaviors in prairie voles (Microtus ochrogaster). Adult, female prairie voles were exposed to 4 weeks of social pairing (control) or isolation, an established stressor for socially monogamous mammals (including humans). Operational measures of depression (sucrose intake and behaviors in the forced swim test), anxiety (behaviors in the elevated plus maze), and aggression (responses to an unrelated prairie vole pup) were investigated. Social isolation induced a progressive decline in sucrose intake and increased immobility time during the forced swim test. Social isolation also decreased the amount of time spent in the open arms of the elevated plus maze, and increased pup-directed attack behavior. The current findings suggest that isolation induces behaviors reflecting elevated negative affect. These results may provide a foundation for creating a rodent model to examine the mechanisms underlying comorbid mood and anxiety disorders.

Behavioural effects of rapid intravenous administration of meta-chlorophenylpiperazine (m-CPP) in patients with generalized social anxiety disorder, panic disorder and healthy controls

Findings from epidemiological, pharmacotherapeutical, genetic and neurobiological studies suggest a possible overlap in the neurobiology of generalized social anxiety disorder (gSAD) and panic disorder (PD). Previously we have found a rapid intravenous m-CPP challenge of 0.1 mg/kg to be highly sensitive and selective in the provocation of panic attacks in patients with PD. We therefore directly compared the behavioural, neuroendocrine and physiological effects of this rapid m-CPP challenge in a small sample of patients with gSAD, patients with PD and matched healthy controls. Panic attacks were significantly more provoked in patients with PD (85%), but not in patients with gSAD (14%) as compared to healthy controls (0%). Effects on the other behavioural parameters, but not on the neuroendocrine and physiological parameters, were significantly greater in patients with PD compared to patients with gSAD and controls. Our preliminary data do not support a shared neurobiology of gSAD and PD.

Prediction of anti-panic properties of escitalopram in the dorsal periaqueductal grey model of panic anxiety

Escitalopram, the active enantiomer of the selective serotonin reuptake inhibitor (SSRI) citalopram, has effects in animal models for the detection of antidepressant and anxiolytic effect and in patients with major depressive and anxiety disorders. In the present study, the effects of escitalopram in the dorsal periaqueductal grey (dPAG) stimulation model of panic anxiety were investigated and compared to a number of clinically used anti-panic agents. The SSRIs, citalopram (ED(50) 6.6mg/kg), fluoxetine (ED(50) 13.6mg/kg), paroxetine (ED(50) 2.9mg/kg) and the benzodiazepine ligand, alprazolam (ED(50) 0.3mg/kg) all reduced the flight-like escape behaviour produced by electrical stimulation of the dPAG in the rat, this is presumed to indicate a reduction in fear and/or physical sensation and is interpreted as an anti-panic effect of the drugs. Escitalopram (ED(50) 3.1mg/kg) also significantly reduced flight behaviour indicating the anti-panic potential of the compound; it is suggested that escitalopram will be twice as potent as citalopram in this context.

Functional magnetic resonance imaging characterization of CCK-4-induced panic attack and subsequent anticipatory anxiety

The main objective of this work was to study the functional markers of the clinical response to cholecystokinin tetrapeptide (CCK-4). Twelve healthy male subjects were challenged with CCK-4 and simultaneously underwent functional magnetic resonance imaging (fMRI) recording. Since anticipatory anxiety (AA) is an intrinsic part of panic disorder, a behavioral paradigm, using the threat of being administered a second injection of CCK-4, has been developed to investigate induced AA. The study was composed of three fMRI scans according to an open design. During first and second scan, subjects were injected with placebo and CCK-4, respectively. The third scan was the AA challenge. CCK-4 administration induced physiological and psychological symptoms of anxiety that met the criteria for a panic attack in 8 subjects, as well as cerebral activation in anxiety-related brain regions. Clinical and physiological response intensity was consistent with cerebral activity extent and robustness. fMRI proved more sensitive than clinical assessment in evidencing the effects of the AA challenge. The latter induced brain activation, different from that obtained on CCK-4 and during placebo injection, that was likely related to anxiety. The method applied in this study is suitable for the study of anxiety using fMRI.

Altered serotonergic function of dorsal raphe nucleus in perinatally protein-deprived rats: effects of fluoxetine administration

We have previously described that perinatally undernourished rats showed increased locus coeruleus activity, a phenomenon reversed by repeated desipramine or fluoxetine administration. Since there is reciprocal modulation between the locus coeruleus and the dorsal raphe nucleus, and because these structures are associated with the pathophysiology of different states of anxiety, we evaluated the activity of serotonergic dorsal raphe neurons from early malnourished animals compared with controls, using in vivo extracellular single-unit recordings. The number of spontaneously active cells/track was significantly higher in protein-deprived animals, although the firing rate and the sensitivity of 5-HT(1A) receptors did not differ from those of controls. Five days of fluoxetine administration (5 mg/kg/day i.p.) was able to reverse the increased number of active serotonergic cells without affecting their firing rate. Furthermore, subsensitivity of 5-HT(1A) autoreceptors developed in the same way after repeated fluoxetine administration in both control and protein-deprived animals. These results suggest that the increased noradrenergic transmission observed in protein-deprived animals may induce an activation of serotonergic neurons in the dorsal raphe nucleus, and that this effect is normalized following fluoxetine treatment, which normalizes locus coeruleus activity.

Challenges in the treatment of anxiety disorders: beyond guidelines

Anxiety disorders are highly prevalent, come in many forms and are often chronic, with many patients requiring long-term maintenance therapy. Anxiety and depression may also be comorbid in up to 50% of patients, leading to problems during diagnosis and treatment. Despite their frequency, the recognition and treatment of anxiety disorders is frequently suboptimal, with as few as 15% of patients obtaining treatment consistent with evidence-based care recommendations. Current treatment guidelines for anxiety disorders include a range of pharmacological and non-pharmacological approaches. However, the use of these guidelines alone may not be sufficient to improve patient outcomes. Optimal treatments for anxiety should be based on chronic disease management and balance efficacy with long-term tolerability. Current first-line therapies should include broad-spectrum agents that have proven efficacy in treating both anxiety and depression and are effective across all treatment phases. The allosteric serotonin reuptake inhibitor (ASRI), escitalopram, is a particularly effective treatment, offering high rates of remission combined with relatively low rates of discontinuation due to adverse events. Combination therapy involving medication and psychological approaches, e.g., cognitive behavioral therapy, may also be helpful. Novel approaches to delivering psychotherapy and self-management via the Internet may address accessibility issues for evidence-based psychological treatments.

Anxiety disorders: under-diagnosed and insufficiently treated

Anxiety disorders have a high prevalence, particularly specific phobia, social anxiety disorder (SAD), post-traumatic stress disorder (PTSD) and generalized anxiety disorder (GAD). The lifetime prevalence for any anxiety disorder is almost 30%. Also, many anxiety disorders have a high rate of comorbid depression, which is generally secondary to the anxiety. Despite high prevalence, anxiety disorders are under-diagnosed, misdiagnosed and inappropriately treated. There is a hierarchy in the lifetime probability of treatment contact, with panic and GAD being diagnosed and treated earlier - possibly as a result of these disorders being the most "visible", unlike SAD, which is characteristically discreet. Under-diagnosis is linked with under-treatment: less than one in five patients with an anxiety disorder receive appropriate medication, which improves to almost one in three for subjects with comorbid depression. For the majority of people with undiagnosed or untreated anxiety disorder, there are many negative consequences, for both the individual and society. These include disability, reduced ability to work leading to loss of productivity, and a high risk of suicide. All of these factors contribute to a reduced quality of life. The economic costs associated with anxiety disorders are large - €48 billion over 28 European countries - and similar to those for dementia. Almost half of the costs are indirect, due to loss of productivity and earnings; the remainder being direct medical and non-medical costs. Current first-line therapies are the antidepressive selective serotonin reuptake inhibitors (SSRIs), with cognitive behavioural therapy a first- or second-line treatment. However, benzodiazepines continue to be prescribed more often than antidepressants. Recent studies have shown that a new type of SSRI, escitalopram (the S-enantiomer of the racemic citalopram), with a unique mode of action, is effective and offers potential as a new treatment for anxiety disorders.

What should animal models of depression model?

In this article, we discuss what animal models of depression should be attempting to 'model'. One must first determine if the goal is to model the regulatory mechanisms by which antidepressant treatments alleviate the various symptoms of depression, or to model the dysregulatory mechanisms underlying the etiology of those symptoms. When modeling the mechanisms of antidepressant effects, a key feature that is often overlooked is the time course required for behavioral efficacy. Even in the clinical literature, there is considerable confusion and inconsistency in defining and identifying 'time of onset' of clinical effect. Although the 'therapeutic lag' may not be as long as has been commonly believed, it does occur. Observable improvement in either global symptomatology or specific symptoms becomes evident after 7-14 days of treatment, and more complete recovery takes considerably longer. Thus, any model addressing potential mechanisms of antidepressant action should exhibit a similar time-dependency. Second, whether attempting to address mechanisms underlying behavioral effects of antidepressants, or the neurobiological substrates underlying the development and manifestation of depression, it is essential to recognize that the syndrome of depression is a diagnostic construct that includes a variety of disparate symptoms, some of which may be related mechanistically, and others that may not be specific to depression, but may cut across categorical diagnostic schemes. Further, it is critical to recognize the close relationship of depression and anxiety. Psychological studies have suggested that the myriad symptoms of depression and anxiety may be subsumed within a more limited number of distinct behavioral dimensions, such as negative affect (neuroticism), positive affect, or physiologic hyperarousal. These dimensions may be related to the functioning of specific neurobiological systems. Thus, rather than trying to recreate or mimic the entire spectrum of symptoms comprising the syndrome of depression, it may be more informative to develop animal models for these behavioral dimensions. Such models may then provide access not only to the neural regulatory mechanisms underlying effective antidepressant treatment, but may also provide clues to the processes underlying the development and manifestation of depression.

Acute hypercarbic gas exposure reveals functionally distinct subpopulations of serotonergic neurons in rats

Although increasing evidence suggests that anatomically defined subpopulations of serotonergic neurons have unique stress-related functional properties, the topographical distribution of the serotonergic neurons involved in responses to stress-related stimuli have not been well-defined. Inspiration of air containing elevated concentrations of carbon dioxide (CO(2); hypercarbic gas exposure) at high concentrations activates both hypothalamic-pituitary-adrenal axis and sympathetic responses in rats and humans. In order to determine the effects of acute hypercarbic gas exposure on subpopulations of topographically organized serotonergic neurons, conscious adult male rats were placed in flow cages and exposed to either atmospheric air or increasing environmental CO2 concentrations (from baseline concentrations up to 20% CO2) for 5min. The presence of immunoreactivity for the protein product of the immediate-early gene c-fos was used as a measure, at the single cell level, of functional cellular responses within subpopulations of serotonergic, noradrenergic and adrenergic neurons. Rats exposed to hypercarbic gas had increased numbers of c-Fos/tryptophan hydroxylase immunoreactive (ir) and c-Fos/tyrosine hydroxylase-ir neurons in specific topographically organized subdivisions of brainstem nuclei, compared to control rats. Within serotonergic cell groups (B1-B9), the most striking effects occurred in a subpopulation of large, multipolar serotonergic neurons within the ventrolateral periaqueductal grey and ventrolateral part of the dorsal raphe nucleus, a region implicated in serotonin-dependent suppression of stress-induced sympathetic outflow and serotonin-dependent inhibition of 'fight or flight' behaviour. These findings have important implications for understanding the role of serotonergic systems in the modulation of stress-related physiology and behaviour and stress-related neuropsychiatric disorders.

Chronic administration of the SSRI fluvoxamine markedly and selectively reduces the sensitivity of cortical serotonergic neurons to footshock stress

We have evaluated, with the use of vertical microdialysis, the effects of fluvoxamine, a selective serotonin reuptake inhibitor (SSRI) on the increase in serotonin and norepinephrine output elicited in rats prefrontal cortex by exposure to footshock stress. Exposure to footshock stress induced a marked increase in the cortical extracellular concentration of both serotonin and norepinephrine (+70% and +100%, respectively) in control rats. Long term, but not acute administration of fluvoxamine (10 mg/kg, i.p. once a days for 21 days) completely antagonized the stress induced increase in cortical serotonin extracellular concentration, while failed to modify the sensitivity of cortical noradrenergic neurons to the same stressful stimulus. Our results have shown that it is possible to independently modulate the sensitivity of cortical serotonergic neurons to stressful stimuli without altering the responsiveness of noradrenergic neurons to the same stress. Given the different role played by serotonin and norepinephrine in the modulation of the stress response, the availability of drugs able to selectively modulate the plastic response of serotonergic neurons to stress in specific brain areas might be important for the pharmacotherapy of anxiety disorders.

1st International Conference on Panic Attacks: diversity of theories and treatments

The 1st International Conference on Psychophysiology of Panic Attacks focused on the diversity of treatments and theories in this complex condition. Experimental research topics were featured, as well as treatment strategies, case studies and patient perspectives. The conference aimed to create a strong multi-cultural emphasis through international, interdisciplinary and patient-professional interaction. The experimental techniques of lactate provocation of panic, carbon dioxide provocation, respiratory measures and cholecystokinin tetrapeptide infusion were used in various ongoing studies aimed at investigating familial markers, protocols for inducing panic in subjects (including opioid-receptor blockade), brain stem mechanisms involved in mediating anxiety and correlation of respiratory variability with panic severity and treatment outcome. Internet-based questionnaire surveys of panic attack (PA) in subjects that had been sexually abused and of subjective feelings about PAs in patients undergoing fertility treatment were presented, as was a survey of panic epidemiology in Iranian students. Some novel treatment modes were discussed, including non-verbal imagery and art therapy and a telephone-conferencing delivery of cognitive-behavioural therapy. Several case studies were used to illustrate treatments and a personal account of panic disorder combined some time after onset with post-traumatic stress disorder highlighted the different responses of the two disorders to psychotherapies.

Panic disorder

BACKGROUND

This article reviews the clinical features, epidemiology, pathophysiology, dental findings, and dental and medical management of the care of patients with panic disorder, or PD.

TYPES OF STUDIES REVIEWED

The authors conducted a MEDLINE search for the period 1998 through 2003, using the key term "panic disorder" to define the pathophysiology of the disorder, its epidemiology and dental implications. The articles they selected for further review included those published in peer-reviewed journals.

RESULTS

PD is a common and debilitating psychiatric disease in which a person experiences sudden and unpredictable panic attacks, or PAs, with symptoms of overwhelming anxiety, chest pain, palpitations and shortness of breath. Persistent concern about having another attack and worry that it may indicate a heart attack or "going crazy" impairs the person's social, family and working lives. Frequently accompanying the disorder is agoraphobia, depression and mitral valve prolapse, or MVP.

CLINICAL IMPLICATIONS

In patients with PD, the prevalence of dental disease may be extensive because of the xerostomic effects of psychiatric medications used to treat it. Dental treatment consists of preventive dental education and prescribing saliva substitutes and anticaries agents. Precautions must be taken when prescribing or administering analgesics, antibiotics or sedative agents that may have an adverse interaction with the psychiatric medications. Because there is a connection between PAs and MVP, the dentist needs to consult with the patient's physician to determine the presence of MVP and whether there is associated mitral valve regurgitation. Patients with MVP and accompanying mitral valve regurgitation require prophylactic antibiotics when undergoing dental procedures known to cause a bacteremia and heightened risk of endocarditis.

The role of serotonin in panic: evidence from tryptophan depletion studies

There has been growing interest in the role of serotonin (5-hydroxytryptamine, 5-HT) in anxiety, including pathological states such as panic disorder. The technique of tryptophan depletion (TD), which causes an acute, temporary and reversible reduction in brain 5-HT levels, is a useful minimally invasive paradigm to aid the research of the role of 5-HT in various disorders. This review discusses the evidence supporting the hypothesis that 5-HT function is of importance in the neurobiology of panic disorder and considers in more detail how our understanding has been influenced by work using the technique of TD. Possible avenues for future research are also discussed.

Antagonism of the stress-induced increase in cortical norepinephrine output by the selective norepinephrine reuptake inhibitor reboxetine

We have previously shown that long-term treatment of rats with antidepressant drugs that affect the activity of noradrenergic and serotonergic neurons by different mechanisms, inhibits the increase in cortical norepinephrine output induced by stress. With the use of microdialysis, we have now evaluated the effects of reboxetine, an antidepressant drug that selectively inhibits norepinephrine reuptake, on the increase in cortical norepinephrine output elicited in rats by exposure to foot-shock stress or by the acute administration of N-methyl-beta-carboline-3-carboxamide (FG 7142) (20 mg/kg, i.p.). Foot-shock stress and FG 7142 each induced a marked increase in the cortical extracellular concentration of norepinephrine (+200 and +90%, respectively) in control rats. Long-term treatment with reboxetine (10 mg/kg, i.p., once a day for 21 days) reduced the effect of foot-shock stress and completely antagonized the effect of FG 7142 on cortical norepinephrine output. Our results suggest that changes in the activity of noradrenergic neurons in the cortex might be relevant to the anxiolytic and antidepressant effects of reboxetine.

Pharmacological therapies in fibromyalgia

The fibromyalgia syndrome (FMS) is a common, chronic, widespread pain disorder that mainly affects middle-aged women. In addition to pain complaints, fatigue and disturbed sleep are symptoms frequently reported by these patients. Many FMS patients also meet diagnostic criteria for mood disorders (e.g. depression) as well as other so-called 'functional somatic syndromes', including irritable bowel syndrome, temporomandibular joint disorder, and subsets of chronic low-back pain. A wide variety of medications are used to manage the eclectic symptomatology of FMS patients, although relatively few have been rigorously tested. This chapter provides a contemporary update of the state of FMS pharmacotherapy, with an emphasis on compounds that have been tested in double-blind, randomized, controlled trials. Particular attention is paid to the efficacy of these therapies on the associated symptoms and co-morbid syndromes commonly seen in FMS patients.

The neurobiology and control of anxious states

Fear is an adaptive component of the acute "stress" response to potentially-dangerous (external and internal) stimuli which threaten to perturb homeostasis. However, when disproportional in intensity, chronic and/or irreversible, or not associated with any genuine risk, it may be symptomatic of a debilitating anxious state: for example, social phobia, panic attacks or generalized anxiety disorder. In view of the importance of guaranteeing an appropriate emotional response to aversive events, it is not surprising that a diversity of mechanisms are involved in the induction and inhibition of anxious states. Apart from conventional neurotransmitters, such as monoamines, gamma-amino-butyric acid (GABA) and glutamate, many other modulators have been implicated, including: adenosine, cannabinoids, numerous neuropeptides, hormones, neurotrophins, cytokines and several cellular mediators. Accordingly, though benzodiazepines (which reinforce transmission at GABA(A) receptors), serotonin (5-HT)(1A) receptor agonists and 5-HT reuptake inhibitors are currently the principle drugs employed in the management of anxiety disorders, there is considerable scope for the development of alternative therapies. In addition to cellular, anatomical and neurochemical strategies, behavioral models are indispensable for the characterization of anxious states and their modulation. Amongst diverse paradigms, conflict procedures--in which subjects experience opposing impulses of desire and fear--are of especial conceptual and therapeutic pertinence. For example, in the Vogel Conflict Test (VCT), the ability of drugs to release punishment-suppressed drinking behavior is evaluated. In reviewing the neurobiology of anxious states, the present article focuses in particular upon: the multifarious and complex roles of individual modulators, often as a function of the specific receptor type and neuronal substrate involved in their actions; novel targets for the management of anxiety disorders; the influence of neurotransmitters and other agents upon performance in the VCT; data acquired from complementary pharmacological and genetic strategies and, finally, several open questions likely to orientate future experimental- and clinical-research. In view of the recent proliferation of mechanisms implicated in the pathogenesis, modulation and, potentially, treatment of anxiety disorders, this is an opportune moment to survey their functional and pathophysiological significance, and to assess their influence upon performance in the VCT and other models of potential anxiolytic properties.

5-HT1A responsivity in patients with panic disorder before and after treatment with aerobic exercise, clomipramine or placebo

Blunted neuroendocrine and physiological responses to the selective 5-HT(1A) receptor agonist, ipsapirone, have been observed in patients with panic disorder and/or agoraphobia (PDA). In order to examine whether this hyporesponsiveness to ipsapirone is modified by pharmacological or non-pharmacological therapeutic interventions, challenges with an oral dose of ipsapirone (0.3 mg/kg) and placebo were performed in patients with PDA before and after 10 weeks of treatment with clomipramine, aerobic exercise and placebo. Before treatment, administration of ipsapirone was followed by significant increases of cortisol, anxiety and other psychopathological symptoms in comparison to the placebo challenge. In addition, a significant decrease of body temperature was observed. After the 10-week treatment period, the psychological responses to ipsapirone were significantly reduced in the clomipramine and the exercise group. In contrast, there was a non-significant trend towards higher cortisol responses after clomipramine and exercise treatment. The hypothermic response to ipsapirone was significantly reduced by clomipramine treatment. In conclusion, our results demonstrate that effective treatment of panic disorder has divergent effects on the psychological, neuroendocrine and temperature responses to ipsapirone.

Pharmacotherapy of anxious disorders

The present paper is a review of the treatment of anxious disorders by the current pharmaceutical medications; a short epidemiological survey is given for anxious disorders including: general anxiety disorder, panic disorder, obsessive compulsive disorder, social anxiety and post-traumatic stress disorder. For all these disorders there are proposals of treatment built on literature data mainly on meta-analysis as well on personal experience.

Further evidence for the predictive validity of the unstable elevated exposed plus-maze, a behavioural model of extreme anxiety in rats: differential effects of fluoxetine and chlordiazepoxide

The unstable elevated exposed plus-maze (UEEPM) is a novel model of extreme anxiety which elicits unconditioned flight/escape behaviour in rats. The current studies aimed to investigate further the predictive validity of the paradigm, by examining the effects on UEEPM behaviour of both clinically effective (chronic fluoxetine) and ineffective (acute fluoxetine and chlordiazepoxide) treatments for panic disorder. In the first experiment, male Brown Norway rats received a single injection of fluoxetine (1.0-10.0 mg/kg p.o.) or chlordiazepoxide (CDP, 1.0-10.0 mg/kg i.p.) 30 min prior to UEEPM exposure. In the second experiment, in order to assess the effects of chronic dosing or handling on baseline UEEPM behaviour, subjects received either 21 days vehicle injection (p.o.) or handling, before being exposed to the test. Finally, rats received 21 days fluoxetine (1.0-10.0 mg/kg) in their food, before being tested in the UEEPM. Acute CDP and fluoxetine had no effect on UEEPM behaviour. Chronic handling and vehicle administration (p.o.) significantly reduced escape in the UEEPM, hence preventing the effects of chronic fluoxetine administration from being investigated by p.o. dosing. Chronic fluoxetine in subjects' food (10.0 mg/kg) significantly attenuated animals' propensity to escape from the UEEPM. The results further support the pharmacological similarity between symptoms of panic in humans and escape in the UEEPM and suggest that the UEEPM may represent a paradigm to facilitate investigation into the neurochemical basis of extreme anxiety disorders.

Paroxetine: an update of its use in psychiatric disorders in adults

Paroxetine is a selective serotonin reuptake inhibitor (SSRI), with antidepressant and anxiolytic activity. In 6- to 24-week well designed trials, oral paroxetine 10 to 50 mg/day was significantly more effective than placebo, at least as effective as tricyclic antidepressants (TCAs) and as effective as other SSRIs and other antidepressants in the treatment of major depressive disorder. Relapse or recurrence over 1 year after the initial response was significantly lower with paroxetine 10 to 50 mg/day than with placebo and similar to that with imipramine 50 to 275 mg/day. The efficacy of paroxetine 10 to 40 mg/day was similar to that of TCAs and fluoxetine 20 to 60 mg/day in 6- to 12-week trials in patients aged > or =60 years with major depression. Paroxetine 10 to 40 mg/day improved depressive symptoms to an extent similar to that of TCAs in patients with comorbid illness, and was more effective than placebo in the treatment of dysthymia and minor depression. Paroxetine 20 to 60 mg/day was more effective than placebo after 8 to 12 weeks' treatment of obsessive-compulsive disorder (OCD), panic disorder, social anxiety disorder (social phobia), generalised anxiety disorder (GAD) and post-traumatic stress disorder (PTSD). Improvement was maintained or relapse was prevented for 24 weeks to 1 year in patients with OCD, panic disorder, social anxiety disorder or GAD. The efficacy of paroxetine was similar to that of other SSRIs in patients with OCD and panic disorder and similar to that of imipramine but greater than that of 2'chlordesmethyldiazepam in patients with GAD. Paroxetine is generally well tolerated in adults, elderly individuals and patients with comorbid illness, with a tolerability profile similar to that of other SSRIs. The most common adverse events with paroxetine were nausea, sexual dysfunction, somnolence, asthenia, headache, constipation, dizziness, sweating, tremor and decreased appetite. In conclusion, paroxetine, in common with other SSRIs, is generally better tolerated than TCAs and is a first-line treatment option for major depressive disorder, dysthymia or minor depression. Like other SSRIs, paroxetine is also an appropriate first-line therapy for OCD, panic disorder, social anxiety disorder, GAD and PTSD. Notably, paroxetine is the only SSRI currently approved for the treatment of social anxiety disorder and GAD, which makes it the only drug of its class indicated for all five anxiety disorders in addition to major depressive disorder. Thus, given the high degree of psychiatric comorbidity of depression and anxiety, paroxetine is an important first-line option for the treatment of major depressive disorder, OCD, panic disorder, social anxiety disorder, GAD and PTSD.