Antidepressant drugs in anxiety disorders

Pharmacotherapy and cognitive bias modification for the treatment of anxiety disorders

INTRODUCTION

Anxiety disorders are characterized by widespread and persistent anxiety or recurrent panic attacks. As a result of their high prevalence, chronicity, and comorbidity, patients' quality of life and functioning are severely compromised. However, several patients do not receive treatment.

AREAS COVERED

This review discusses the effectiveness, safety, and limitations of major medications and cognitive bias modification (CBM) for treating anxiety disorders. The possibility of combined treatment is also discussed in the literature. Furthermore, drawing on Chinese cultural perspectives, the authors suggest that anxiety can be recognized, measured, and coped with at three levels of skill (), vision (), and Tao ().

EXPERT OPINION

The combination of pharmacotherapy and CBM is possibly more effective in treating anxiety disorders than either treatment alone. However, clinicians and patients should participate in the joint decision-making process and consider comprehensive factors. Moderate anxiety has adaptive significance. In the coming years, by combining the downward analytical system of western culture with the upward integrative system of Chinese culture, a comprehensive understanding of anxiety and anxiety disorders should be established, rather than focusing only on their treatment.

Incidence of early anxiety aggravation in trials of selective serotonin reuptake inhibitors in depression

OBJECTIVE

Selective serotonin reuptake inhibitors (SSRIs) may aggravate anxiety and agitation during the first days of treatment but the frequency of such reactions remains unknown.

METHOD

We analysed patient-level data from placebo-controlled trials of sertraline, paroxetine or citalopram in depressed adults. Somatic anxiety, psychic anxiety and psychomotor agitation as assessed using the Hamilton Depression Rating Scale (HDRS) were analysed in all trials (n = 8262); anxiety-related adverse events were analysed in trials investigating paroxetine and citalopram (n = 5712).

RESULTS

After one but not two weeks, patients on an SSRI were more likely than those on placebo to report enhanced somatic anxiety (adjusted risk 9.3% vs. 6.7%); likewise, mean rating of somatic anxiety was higher in the SSRI group. In contrast, patients receiving an SSRI were less likely to report aggravation of psychic anxiety (adjusted risk: 7.0% vs. 8.5%) with mean rating of psychic anxiety and agitation being lower in the SSRI group. The adverse event 'nervousness' was more common in patients given an SSRI (5.5% vs. 2.5%). Neither aggravation of HDRS-rated anxiety nor anxiety-related adverse events predicted poor antidepressant response.

CONCLUSION

Whereas an anxiety-reducing effect of SSRIs is notable already during the first week of treatment, these drugs may also elicit an early increase in anxiety in susceptible subjects that however does not predict a poor subsequent response to treatment.

The Mouse Defense Test Battery: pharmacological and behavioral assays for anxiety and panic

The Mouse Defense Test Battery was developed from tests of defensive behaviors in rats, reflecting earlier studies of both acute and chronic responses of laboratory and wild rodents to threatening stimuli and situations. It measures flight, freezing, defensive threat and attack, and risk assessment in response to an unconditioned predator stimulus, as well as pretest activity and postthreat (conditioned) defensiveness to the test context. Factor analyses of these indicate four factors relating to cognitive and emotional aspects of defense, flight, and defensiveness to the test context. In the Mouse Defense Test Battery, GABA(A)-benzodiazepine anxiolytics produce consistent reductions in defensive threat/attack and risk assessment, while panicolytic and panicogenic drugs selectively reduce and enhance, respectively, flight. Effects of GABA(A)-benzodiazepine, serotonin, and neuropeptide ligands in the Mouse Defense Test Battery are reviewed. This review suggests that the Mouse Defense Test Battery is a sensitive and appropriate tool for preclinical evaluation of drugs potentially effective against defense-related disorders such as anxiety and panic.

Antidepressant use in psychiatry and medicine: importance for dental practice

BACKGROUND

Many dental patients receive antidepressant therapy. However, antidepressants taken with other drugs may increase the risk of complications that require special dental precautions and care.

METHODS

The authors conducted a retrospective study of 1,800 randomly selected patient records and evaluated the prevalence of using antidepressants and other medications concurrently. They analyzed antidepressant intake relative to drug classification and mechanism of action, age, sex and associated potential for clinical complications such as xerostomia, orthostatic hypotension and interaction with vasoconstrictors. The potential for additive adverse effects between antidepressants and other medications also was analyzed.

RESULTS

Three hundred eighty-one (21 percent) of the 1,800 patient records indicated that patients were being treated with 412 antidepressants. Female subjects out-numbered male subjects by an approximate 2.3:1 ratio. Selective serotonin reuptake inhibitors were most commonly prescribed, followed by tricyclic antidepressants, atypical and third-generation antidepressants, and monoamine oxidase inhibitors. Based on reported medication intake, almost 58 percent of subjects in the antidepressant group were receiving treatment with two or more medications that had the potential for producing xerostomia. Two hundred fifty-seven (67 percent) of the 381 records documented intake of an antidepressant or other medication with orthostatic hypotension potential.

CONCLUSIONS

Three hundred eighty-one patients reported that they were receiving antidepressant therapy for psychiatric and other medical reasons. Potential adverse effects and interactions with other medications have direct implications for dental treatment.

CLINICAL IMPLICATIONS

Patients receiving antidepressant therapy are at risk of developing xerostomia and orthostatic hypotension, as well as experiencing the adverse effects of interaction with vasoconstrictors. Dentists must take appropriate precautions in treating these patients.

The prediction of nonresponse to pharmacotherapy in panic disorder: a review

Several effective pharmacotherapeutic treatments exist for panic disorder; however, not all patients respond to treatment: between 20% to 40% are non-responders. Recent studies have reported several predictors of nonresponse to pharmacotherapy. In this review two questions are addressed: is there consensus with respect to predictors of nonresponse and are there any differences between short-term and long-term predictors? In this review both short-term and long-term outcome studies are discussed. Studies were included if at least DSM-III criteria were used and baseline variables were investigated as possible predictor of response, or nonresponse, to pharmacotherapy. Of each clinical predictor, tallies were made of the particular predictors employed and of those predictors that predicted nonresponse. It appears that a long duration of illness and severe agoraphobic avoidance are robust predictors of nonresponse, particularly in long-term studies. Personality disorders, or even personality traits, are possibly the most robust predictors of nonresponse. Several factors appear to be robust predictors of nonresponse: factors that are present before treatment and exert their influence on short-term and long-term treatment outcome. Prospective studies are needed to further investigate these factors and to test whether it is viable to intervene in an attempt to increase treatment response.

Respiratory and cognitive subtypes of panic. Preliminary validation of Ley's model

A review of the panic disorder literature strongly suggests subtypes of panic attacks, including a respiratory subtype. This study empirically tested several aspects of Ley's panic subtype theory, measuring end-tidal carbon dioxide (ETCO2) levels at baseline, during psychologic and respiratory stressors, and at recovery. As predicted, Type 1 (classic or respiratory) panickers had significantly lower resting ETCO2 compared to Type 3 (cognitive) and to controls. Type 3 panickers did not differ from controls. Physiologic findings support the existence of respiratory and other subtypes of panic attacks in panic disorder. More complex measures of respiration and other physiology are likely required to elicit full subtype profiles. Distinguishing between chronic (compensated) hyperventilators and acute hyperventilators will likely be useful in clarifying the subtypes. Recognizing the need for differential diagnosis of panic attacks can facilitate developing more specific treatment plans and interventions (e.g., restoration of normal ETCO2 in Type 1), improving treatment success rates.

Serum levels of clomipramine and desmethylclomipramine and clinical improvement in panic disorder

Several placebo-controlled trials have shown the efficacy of clomipramine (CMI) in panic disorder. However, none has investigated the relationship between CMI, and desmethylclomipramine (DCMI) plasma levels, and outcome. In this trial, 41 patients meeting the DSM-III-R criteria for panic disorder with/without agoraphobia received 50-200 mg of CMI daily in a single-blind, flexible dose regimen for 14 weeks. At the end of treatment, 97% of the patients were free of panic attacks. Patients were classified into two groups of improvement according to the panic symptom items of the 'Patient-Rated Anxiety Scale'. A repeated-measures analysis of variance suggested a significant association between outcome and serum DCMI level/daily dose ratio as well as total serum level/daily dose. Patients with intense improvement showed DCMI and total serum levels lower than those with moderate improvement. The results indicate the importance of monitoring clomipramine and desmethylclomipramine serum levels in this disorder.

A double-blind crossover comparison of clomipramine and desipramine in the treatment of panic disorder

OBJECTIVE

To compare the efficacy of clomipramine hydrochloride (CMI), a serotonin reuptake inhibitor with the noradrenergic tricyclic antidepressant agent, and desipramine hydrochloride (DMI) for patients with panic disorder (PD).

METHOD

Following a 2-week, single-blind placebo washout phase, 17 PD outpatients completed a 16-week, double-blind, crossover comparison of CMI and DMI. Key outcome measures included panic attacks frequency, the NIMH Global Scales for Anxiety, Depression and Impairment, Hamilton Anxiety Scale (Psychic and Somatic Subscales), Zung Anxiety Inventory (Raw and Index Subscales) and the Spielberger State Anxiety Scale.

RESULTS

Both CMI and DMI led to significant improvement from baseline placebo state in panic attacks frequency and behavioral ratings (p<0.001). CMI led to a greater reduction in the frequency of panic attacks (p=0.028) and was superior to DMI on ratings of anxiety: NIMH Global Anxiety, Zung Anxiety Scale (Raw and Index) and the Spielberger Anxiety Scale. No difference was found between the drugs on the NIMH Global Impairment Scale and the Hamilton Somatic and Psychic Scales.

CONCLUSION

Both drugs appeared to have significant therapeutic effects in patients with PD, but CMI appeared to be more effective. The effectiveness of the serotonergic drug suggests that the role of the serotonergic system in the pathogenesis of PD should be further explored.

Serotonergic compounds in panic disorder, obsessive-compulsive disorder and anxious depression: A concise review

The recognition that antidepressants are effective in panic and anxiety disorders had led to the evaluation of drugs selective for serotonin uptake in an attempt to dissect the neurotransmitters responsible for panic disorder. Fluvoxamine is the best studied of the selective serotonin reuptake inhibitors (SSRIs) and recent double-blind studies have confirmed earlier findings showing a reduced number and duration of panic attacks. In addition, fluvoxamine attenuates the 'accessory symptoms' of panic disorder such as depression and anxiety. Fluoxetine has only been evaluated in open trials, although these results are generally positive. Paroxetine has shown similar efficacy to clomipramine in a large, controlled study, although the other SSRIs have seldom been investigated. Fluvoxamine lacks the activating properties possessed by some SSRIs and this also makes it a useful candidate for the treatment of anxious depression. The efficacy of fluvoxamine in obsessive-compulsive disorder has been established in several double-blind, placebo-controlled trials. In clinical terms, fluvoxamine is approximately as effective as clomipramine, but with a decidedly better adverse event profile. Fluoxetine has also proved effective in obsessive-compulsive disorder, although a recent meta-analysis suggests that fluvoxamine may be somewhat more effective. The other SSRIs have not been sufficiently well studied to justify conclusive statements.

Phobic symptoms as predictors of nonresponse to drug therapy in panic disorder patients (a preliminary report)

Factors that predict nonresponse to drug therapy (brofaromine or fluvoxamine) were investigated in a sample of 44 panic disorder patients. We used a strict definition of nonresponse to find patients who did not respond at all after 12 weeks of treatment. Using this definition, 15 patients (32.6%) were considered nonresponders. Nonresponders had a higher score on the Blood-Injury subscore of the Fear Questionnaire (FQ) and more often had high scores on several FQ subscores, indicative of comorbid phobic symptoms. These variables were subsequently used to predict nonresponse.

Three years follow-up of panic disorder patients: a naturalistic study

Forty Danish panic disorder patients participating in a placebo controlled study of alprazolam and imipramine (The Cross National Collaborative Panic Study, Phase II) were followed up by a telephone interview three years later, with essentially the same battery of evaluation procedures applied at baseline, end of study, and follow-up. The main finding was that panic disorder is a chronic disorder, but fluctuating in form and severity in the course of time. Twenty-five percent of the patients no longer fulfilled the DSM-III criteria for panic disorder, but had substantial disability due to a variety of symptoms, including panic attacks at infrequent rate, generalized anxiety symptoms, affective symptoms, and phobic avoidance behavior. Nearly three fourths of the patients were under treatment at follow-up. Benzodiazepines were the drugs most often prescribed, usually in combination with supportive psychotherapy. It was concluded that the different types of treatment offered were insufficient. Variables predicting panic disorder or substantial disability at 3-years follow-up were few.

Drug treatment of panic disorder

Drug treatment of panic disorder is reviewed with focus on recent controlled studies. The efficacy of alprazolam, a triazolobenzodiazepine, and imipramine, a tricyclic antidepressant, has consistently been demonstrated, but there is reasonable evidence that other benzodiazepines or antidepressants might also be effective if equipotent doses are used. Most controlled studies demonstrate drug efficacy on several psychopathological symptoms, including the core symptom panic attacks. Limited evidence indicates that alprazolam may be more efficacious in treating panic attacks than avoidance behaviour, and the reverse when imipramine is concerned. Drug efficacy appears to be most consistently documented in moderately to severely ill panic patients. The benzodiazepines are better tolerated than antidepressants in terms of patient acceptance, and the improvement sets in faster with benzodiazepines. In the presence of depressive symptoms considered secondary to panic attacks and/or agoraphobia, both types of drugs appear efficacious. Difficulty discontinuing high-dose benzodiazepine treatment remains the most important side effect of the treatment but sedation can, like anticholinergic side effects of the tricyclic antidepressants, be troublesome, thereby diminishing patient compliance. The role of newly developed antidepressants with a more specific mode of action and milder side effects awaits evaluation in controlled trials.

Long-term drug treatment of panic disorder

Drug treatment of panic disorder with benzodiazepines and antidepressants has been established as efficacious in the short-term (6-8 weeks). The efficacy of medications during long-term (i.e., continuous) treatment has not often been addressed and a review of the evidence is presented. Most data exists for the long-term effectiveness of benzodiazepines. Experience with the triazolobenzodiazepine, alprazolam, is reviewed together with some other high potency drugs, e.g., clonazepam. Tricyclic antidepressants are also effective in the long-term treatment of panic and the relevant studies are presented. Long-term efficacy for monoamine oxidase inhibitors is not as clearly established. The issue of relapse following drug withdrawal is addressed and some strategies for patient management in long-term therapy are discussed.

MAO inhibitors in panic disorder: clinical effects of treatment with brofaromine. A double blind placebo controlled study

There is considerable evidence that antidepressants, particularly serotonin uptake inhibitors, are effective in the treatment of panic disorder (PD). Monoamine oxidase inhibitors (MAOI) may also have beneficial effects in PD. In this study 30 patients with PD with or without agoraphobia (DSM-III-R) were treated with the selective and reversible MAO-A inhibitor brofaromine (150 mg daily) in a 12-week double-blind placebo controlled design. A clinical relevant improvement was found in more than 70% of the patients treated with brofaromine, whereas no significant improvement was observed on placebo. After an increase in anxiety in the first week, a clinically relevant improvement in anxiety symptoms was found, followed by a subsequent reduction in agoraphobic avoidance in patients treated with brofaromine. A similar improvement was observed on distress scores related to panic attacks, although there was no significant reduction in the number of panic attacks. The most prominent side-effects were middle sleep disturbance and nausea. No increase in blood pressure was observed. During a follow-up period of another 12 weeks a further improvement was found in patients treated with brofaromine.

Clomipramine, a better reference drug for panic/agoraphobia. I. Effectiveness comparison with imipramine

An 8-week, double-blind, flexible-dose trial comparing low doses of clomipramine (mean=50 mg) with moderate doses of imipramine (mean=113.8 mg and propanteline (active placebo), was carried out in 60 out-patients with panic disorder with or without agoraphobia. Efficacy evaluation included global, anxiety and depression rating scales, and the determination of rates of relapse over up to 10 weeks of single-blind placebo follow-up. Both tricyclics were significantly more effective than propanteline, but clomipramine tended to act faster and more consistently than imipramine on most measures. Given the degree of blindness achieved and the significantly lower doses of clomipramine, this seems a better reference drug than imipramine for clinical trials in panic/agoraphobia.

Clomipramine effectively reduces premenstrual irritability and dysphoria: a placebo-controlled trial

Forty nondepressed women displaying severe premenstrual irritability and/or dysphoria and fulfilling the DSM-III-R criteria of late luteal phase dysphoric disorder were treated daily for 3 menstrual cycles with either the potent serotonin reuptake inhibitor clomipramine (25-75 mg; flexible dosage) (n = 20) or placebo (n = 20). In both treatment groups premenstrual irritability and dysphoria (as rated daily by the patients using a visual analogue scale) were significantly reduced as compared with the rating during 2 pretreatment reference cycles; however, in the placebo group this reduction was only about 40% whereas, in the clomipramine group, the symptom decrease was greater than 80%. At all 3 treatment cycles, patients on clomipramine displayed significantly lower symptom rating than controls. Also with respect to the rating of global improvement, the results obtained with clomipramine were considerably and significantly better than those obtained with placebo. It is concluded that low doses of clomipramine effectively reduce premenstrual irritability and dysphoria with a response rate close to 100%. The possible role of serotonin in the pathophysiology of the premenstrual syndrome is discussed.

Higher postdexamethasone serum cortisol levels in agoraphobic than in nonagoraphobic panic disorder patients

The dexamethasone suppression test (DST) was performed in panic disorder (PD) patients with (n = 32) or without (n = 31) agoraphobia and in normal controls (n = 49). Postdexamethasone serum cortisol levels were significantly higher in agoraphobic PD patients (105.3 +/- 19.3 nmol/L) both when compared to PD patients without agoraphobia (47.3 +/- 7.7 nmol/L; p less than 0.01) and when compared to healthy controls (51.7 +/- 8.3 nmol/L; p less than 0.01). The rate of nonsuppressors (i.e., subjects displaying postdexamethasone cortisol levels greater than 138 nmol/L) was 28% and 3% in agoraphobic and nonagoraphobic PD patients, respectively, and 12% in controls. In patients, the postdexamethasone cortisol levels did not correlate with the number of panic attacks per week, baseline anxiety as measured using the Hamilton Anxiety Scale, depressive symptoms as measured using the Montgomery-Asberg Depression scale, or duration of illness. Data from eight patients in whom a second DST was performed after treatment with imipramine or clomipramine for three months indicate that a marked reduction of the number of anxiety attacks is not necessarily accompanied by a normalization of a pathological DST. In conclusion, it is suggested that the elevated postdexamethasone cortisol levels sometimes observed in agoraphobic PD patients are more closely related to the agoraphobic behavior than to the panic attacks per se.

Efficacy and safety of alprazolam, imipramine and placebo in treating panic disorder. A Scandinavian multicenter study

As part of the cross-national collaborative panic study, a double-blind comparison of alprazolam, imipramine and placebo was performed in Scandinavian outpatients with panic disorder according to DSM-III; 41 patients were randomly allocated to each drug. Doses were increased for 3 weeks to an average of about 6 mg alprazolam, 150 mg imipramine and a corresponding number of placebo capsules, which were then given for 5 weeks. No more than supportive psychotherapy was given. Key symptoms were rated weekly. The drugs were tapered for 4 or 8 weeks and the patients were followed up for 6 months. Compliance at 3 weeks was 95% for alprazolam, 83% for imipramine and 88% for placebo; at 8 weeks 95% for alprazolam, 73% for imipramine and 46% for placebo. At 3 weeks plasma determination showed that the proportion taking diazepam outside the protocol was 0% for alprazolam, 19% for imipramine and 31% for placebo; at 8 weeks the corresponding proportions were 3%, 11% and 16%. Intention-to-treat analysis showed that freedom from panic attacks was obtained for 68% with alprazolam, 61% with imipramine and 34% with placebo. Alprazolam was more effective than imipramine and placebo on anticipatory anxiety and phobic symptoms. Globally rated by physicians and patients, about 60% had complete remission with alprazolam and imipramine and 30% on placebo. At least partial remission was obtained in about 85% with alprazolam, 70% with imipramine and 40% with placebo. Alprazolam had a more rapid onset of action than imipramine on all symptoms. Side effects were generally mild, with a preponderance of drowsiness for alprazolam and anticholinergic effects for imipramine. Tapering was uneventful without significant discontinuation phenomena. During taper and follow-up, several patients in remission relapsed, leaving approximately 30% patients in complete remission in all groups. To obtain more stable improvement, either long-term drug treatment or combinations of drug treatment and psychotherapy should be evaluated.

Cerebrospinal fluid levels of monoamine metabolites in panic disorder

The cerebrospinal fluid (CSF) levels of the serotonin metabolite 5-hydroxyindoleacetic acid (5HIAA), the noradrenaline metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG), and the dopamine metabolite homovanillic acid (HVA) did not differ significantly in a group of patients with panic disorder (n = 17) as compared to age- and sex-matched normal controls (n = 17). While CSF concentrations of HVA and 5HIAA were significantly correlated in both patients and controls, CSF MHPG levels were significantly correlated with the concentrations of CSF 5HIAA and HVA only in patients. In a small number of subjects (n = 5), successful reduction of anxiety attacks by administration of clomipramine or imipramine (50-150 mg/day) for at least 2 months was associated with a significant decrease in CSF concentrations of 5HIAA and MHPG, but not HVA.

Alpha 1- and beta-adrenoceptor stimulation potentiate the anticonflict effect of a benzodiazepine

Interactions between different noradrenaline (NA)-active drugs and the benzodiazepine alprazolam (APZ) were examined in a modified Vogel's drinking conflict test in the rat. In a dose (0.5 mg/kg) which did not alter the behavior by itself, the alpha 2-adrenoceptor antagonist yohimbine consistently was found to enhance the anticonflict effect of APZ (0.5 mg/kg). The yohimbine induced potentiation of the APZ effect was counteracted both by the selective alpha 1-adrenoceptor antagonist prazosin (0.25 mg/kg) and the beta-adrenoceptor antagonist propranolol (2.0 mg/kg), but not by the selective beta 1-adrenoceptor antagonist metoprolol (2.0 mg/kg). Similar potentiating phenomena were obtained after co-administration of APZ (0.5 mg/kg) with the selective alpha 1-adrenoceptor agonist ST 587 (0.5-1.0 mg/kg) as well as with the suggested beta 2-adrenoceptor agonist clenbuterol (1.0 mg/kg). The results indicate that the potentiative effects of alpha 2-adrenoceptor antagonists on BDZ induced anticonflict action may be due to increased stimulation of alpha 1- and beta-adrenoceptors, via enhanced NA release. The findings are discussed in relation to the signal-to-noise hypothesis of NA function, and in relation to the suggested NA involvement in anxiety-related behavior.

Neuropeptide Y: an overview of central distribution, functional aspects, and possible involvement in neuropsychiatric illnesses

Neuropeptide Y (NPY) was first discovered and characterized as a 36-amino-acid peptide neurotransmitter in 1982. It is widely distributed in the central nervous system, with particularly high concentrations within several limbic and cortical regions. A number of co-localizations with other neuromessengers such as noradrenaline, somatostatin, and gamma-aminobutyric acid have been demonstrated. A large number of physiological and pharmacological actions of NPY have been suggested. Recent clinical data also suggest the involvement of NPY in several neuropsychiatric illnesses, particularly in depressive and anxiety states. This article gives a comprehensive review of central distribution of NPY and its receptors, co-localizations and interactions with other neuromessengers, genetic aspects, pharmacological and physiological actions, influence on neuroendocrine functions, and possible involvement in various neuropsychiatric illnesses.

The diagnosis and management of pathological anxiety

The anxiety disorders are common reasons for patients approaching their doctors for help. While benzodiazepines used to be the treatments most commonly used, increasing concern about the wisdom of prescribing these drugs means that other treatments have to be considered. A differential diagnostic schema for patients who complain of anxiety is presented and an outline for counselling these patients is described. Treatment of the four major anxiety disorders is evaluated, and the efficacy of drug treatment compared to various levels of behaviour therapy. Cognitive behaviour therapy is recommended for all four disorders on the grounds of a short-term effectiveness comparable to drug therapy and evidence for stability of improvement after treatment has concluded, evidence that is lacking for the drug therapies.

The pharmacology of human anxiety

The human pharmacology of anxiety disorders, including panic disorder, is detailed. The major theories center around the role of benzodiazepine receptor, noradrenergic and serotonergic dysfunction. The contribution that challenge tests with lactate, hyper- and hypocapnia, beta- and alpha-2-adrenoceptor agonists, peptides, pentylenetetrazol, and caffeine make to our understanding of the biological basis of anxiety and these major theories are described and discussed.

The utility of the panic disorder concept

In this paper we discuss the theory that agoraphobic avoidances are central and spontaneous panics an epiphenomenon to the development of agoraphobia. Moreover we discuss the theory that posits a fixed cognitive-catastrophizing set as causal for panic. We conclude these theories do not fit the facts. We argue that it is important to distinguish between spontaneous panic and chronic or anticipatory anxiety and avoidance. Such a distinction allows for an understanding of the roles of anti-spontaneous panic medications such as tricyclics and MAOI's as well as exposure therapy, in the treatment of panic disorder with agoraphobia. The former serves the purpose of blocking panic attacks while the latter undermines phobic avoidance, but only after the panic attacks have ceased through proper medication. We conclude that recognizing the key role of spontaneous panic and its variants in anxiety nosology is a necessary guide for etiological, psychophysiological and therapeutic research in this rapidly developing area.

Effects of 5-HT1A receptor agonists and L-5-HTP in Montgomery's conflict test

The effects of the pyrimidinyl-piperazines buspirone, gepirone, ipsapirone and their common metabolite 1-(2-pyrimidinyl)-piperazine (PmP) as well as of 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and L-5-hydroxytryptophan (L-5-HTP) were investigated in Montgomery's conflict test--an animal anxiety model based on the animal's inborn urge to explore a new environment and its simultaneous fear of elevated, open spaces. Subcutaneous buspirone (32-128 nmol/kg), gepirone (32-128 nmol/kg), ipsapirone (32-512 nmol/kg) and 8-OH-DPAT (50-200 nmol/kg), as well as intraperitoneal L-5-HTP (56 mumol/kg) produced anxiolytic-like effects. However, at higher doses the magnitude of these effects decreased and overall the dose-response curves displayed inverted U-shapes. The highest doses (2048 nmol/kg) of buspirone and of gepirone even decreased responding below control levels, possibly in part due to concomitant sedation/motor impairment. After L-5-HTP (448 mumol/kg) and PmP (512 nmol/kg) anxiogenic-like effects were observed. The results indicate that anxiolytic- and anxiogenic-like effects of drugs affecting central serotonergic neurotransmission can be obtained in a sensitive rat anxiety model which neither involves consummatory behavior nor punishment. The anxiolytic-like effects of these compounds may be due to their 5-HT1A agonistic properties. Moreover, the present data may provide support for a possible reciprocal association of presynaptic 5-HT1A receptors vs. postsynaptic 5-HT1A as well as 5-HT2 receptors with regard to anxiety.