Behavioral and endocrine responses to clomipramine in panic disorder patients with or without alcoholism

Brain Circulation during Panic Attack: A Transcranial Doppler Study with Clomipramine Challenge

Introduction. Cerebral blood flow has been well studied in patients with panic disorder, but only few studies analyzed the mechanisms underlying the onset of a panic attack. The aim of the present study was to monitor the cerebral hemodynamics modifications during a panic attack. Materials and Methods. 10 panic disorder patients with recent onset, fully drug naïve, were compared to 13 patients with panic disorder with a previous history of treatment and to 14 controls. A continuous bilateral monitoring of mean flow velocities in right and left middle cerebral arteries was performed by transcranial Doppler. Clomipramine was chosen as challenge. Results. Eight out of 10 patients drug naïve and 6 control subjects out of 13 had a full blown panic attack during the test, whereas none of the patients with a history of treatment panicked. The occurrence of a panic attack was accompanied by a rapid decrease of flow velocities in both right and left middle cerebral arteries. Discussion. The bilateral acute decrease of mean flow velocity during a panic attack suggests the vasoconstriction of the microcirculation of deep brain structures perfused by middle cerebral arteries and involved in the so-called "fear circuitry," thus suggesting that cerebral homeostatic dysfunctions seem to have a key role in the onset of a panic attack.

The pharmacology of anxiety

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.

Management of co-morbid anxiety and alcohol disorders: parallel treatment of disorders

Co-morbid alcohol-related disorders and anxiety disorders have been found to occur in alcohol treatment populations, anxiety treatment populations and the general community. People suffering from co-occurring alcohol-related and anxiety disorders are more prone to relapse to alcohol abuse, and more likely to re-enter the treatment system for either disorder than sufferers of either disorder without a co-morbid disorder. To review the current state of the management of this disorder, evidence of the prevalence of this co-morbid condition in clinical and community populations is examined, then the theoretical mechanisms that might explain this connection are reviewed. A comparison of the few treatment studies of co-morbid alcohol and anxiety disorders shows a limited number of pharmacological treatment trials and no psychotherapy outcome trials. This review shows that it is no longer sustainable to conceptualize co-morbidity of alcohol and anxiety disorders as a unitary concept, i.e. lumping alcohol-related and anxiety disorders as one global condition, but as separate distinct combinations of particular anxiety disorders, e.g. alcohol dependence and panic disorder, alcohol dependence and generalize anxiety disorder. The recommended treatment approach, supported by the evidence, is to offer separate and parallel therapy for the alcohol-related and anxiety disorder, until empirical evidence from treatment outcome studies suggest otherwise. There is an urgent need to conduct treatment outcome research for the subtypes of co-morbid alcohol and anxiety disorders.

Molecular targets in the treatment of anxiety

Although the cathecholamine systems have long been the focus of drug therapy in anxiety and depression, the development of novel drugs specifically aimed at new targets within these traditional neurotransmitter systems and at targets outside of these systems is now propelling the field of drug development in anxiety. A greater understanding of regional brain networks implicated in stress, anxiety, and anxious behaviors has provided localized targets for anxiolytics. Within the serotonin and norepinephrine systems, increased understanding of postsynaptic receptor regulation with chronic treatment and cross-system effects of drug therapy have been critical in furthering our understanding of effective pharmacological interventions. Receptors within the glutamate, gamma-aminobutyric acid, and neuropeptide systems provide a rich diversity of drug targets, both in localization and function. While acknowledging significant clinical and biological differences between the various anxiety disorders, an important aspect of modern neurobiological research is to look for similarities among these disorders, given that they are highly comorbid with each other and often respond to the same spectrum of treatments. Here we review current views on both traditional and new molecular targets in the treatment of anxiety, realizing that the ultimate challenge in effective anxiolytic drug development may be achieving specificity in brain regions important in generating and sustaining anxiety.

Psychogenic hearing loss with panic anxiety attack after the onset of acute inner ear disorder

A very rare case of a 50-year-old female showing psychogenic hearing loss with a panic anxiety attack that complicated an acute organic sensorineural hearing loss is reported. At the first visit to our clinic, the patient showed left sensorineural hearing loss with an inner ear disorder pattern. Five days after the onset, her left hearing threshold markedly increased without any subjective signs. On the next day, she suddenly experienced a severe panic attack with anxiety. After the attack, she felt mildly anxious and depressed. A combined therapy using primary corticosteroid therapy for the acute inner ear disorder, psychiatric counseling based on cognitive therapy and the administration of a minor tranquilizer was performed. Her left hearing threshold recovered to within normal ranges except in the high-frequency ranges immediately after the treatment. This case was considered very rare because: (1) the panic anxiety attack occurred in the conversion disorder as psychogenic hearing loss and (2) the psychogenic hearing loss complicated the primary sudden deafness. We suggest that otorhinolaryngologists should have psychiatric knowledge and be able to treat psychogenic hearing loss as a primary care.

The psychobiology of anxiolytic drugs. Part 1: Basic neurobiology

The authors provide an overview of the current state of knowledge with regards to the neurobiological mechanisms involved in normal and pathological anxiety. A brief review of the classification and cognitive psychology of anxiety is followed by a more in-depth look at the neuroanatomical and neurochemical processes and their relevance to our understanding of the modes of action of anxiolytic drugs. The serotonergic, noradrenergic, and gamma-aminobutyric acidergic systems are reviewed. The numerous physiological and pharmacological methods of anxiety provocation and the increasing importance of functional neuroimaging are also examined. The review provides an overview of the biology and basic pharmacology of anxiolytic drugs, and compliments the more clinically oriented companion review.

Increased left posterior parietal-temporal cortex activation after D-fenfluramine in women with panic disorder

It is unclear whether the functional changes found in panic disorder reflect disturbed physiology of particular neurotransmitters. One method of investigating altered neurotransmission is to assess regional brain activations in response to agonist challenges. D-Fenfluramine is a medication that induces neuronal release of serotonin. Using ¿15OH(2)O and positron emission tomography (PET), measurements of regional cerebral blood flow (rCBF) were done at t=-20, -5, +20 and +35 relative to the IV D-fenfluramine injection (t=0) in nine panic-disordered and 18 healthy subjects. Subjects were otherwise healthy, right-handed, non-smoking and not taking psychotropic medication. ¿15OH(2)O PET scans were assessed with Statistical Parametric Mapping using individual global cerebral blood flow as a covariate. Comparisons of the (baseline) first two scans between healthy and panic-disordered subjects showed a decreased rCBF in the left posterior parietal-superior temporal cortex in the patient group. Fenfluramine-induced increases as defined by the last two scans minus the first two scans were compared between groups and a significantly greater increase in the same left posterior parietal-superior temporal region was found in panic-disordered subjects. Consistent with this finding, differences between the last two scans (post-fenfluramine) of the healthy and panic-disordered subjects showed an increased rCBF in the left superior temporal cortex in panic-disordered subjects. Functional pathology in the left parietal-superior temporal cortex in panic disorder may be related to abnormal modulation by serotonin.

Dopamine receptor responsivity in alcoholic patients before and after detoxification

OBJECTIVE

To assess central dopamine receptor responsivity in alcoholic patients during their usual alcohol consumption and after detoxification.

METHOD

Plasma prolactin levels were measured at 0, 30, 60, and 90 min after administration of 5 mg haloperidol i.m. in 21 hospitalized male alcoholic patients during usual alcohol consumption, and 13 days later (mean, range 7-17 days), after detoxification. The test was also performed in seven healthy male volunteers. The patterns of prolactin responses were compared using repeated measures analysis of variance.

RESULTS

The prolactin responses to haloperidol increased significantly after detoxification compared to those during usual alcohol consumption (state x time interaction P < 0.01; planned comparisons for times 0 and 90 min between states P = 0.03). Compared to controls, the responses of the patients before detoxification were lower (group-time interaction P = 0.001), and the difference was not significant after detoxification (P = 0.19). The magnitude of plasma prolactin (PRL) responses were not related to duration of alcohol abuse, score in the Brief Michigan Alcoholism Screening Test (BMAST) scale, or family history of alcoholism.

CONCLUSIONS

Alcohol detoxification is accompanied by a normalization of the low responsivity of central dopaminergic receptors during alcohol abuse. The data support the hypothesis of a participation of the central dopaminergic system in alcohol dependence.

Central serotonergic responsiveness in neurocardiogenic syncope: a clomipramine test challenge

BACKGROUND

Central serotonergic mechanisms appear to participate in the pathogenesis of recurrent neurally mediated syncope. The aim of the study was to investigate the responsiveness of the central serotonergic system by measuring the prolactin and cortisol responses to intravenous administration of the serotonin reuptake inhibitor clomipramine.

METHODS AND RESULTS

Twenty subjects free of any medical treatment were tested. Twelve had a history of recurrent syncopal attacks and positive tilt test (patient group, mean age 47+/-18 years, 8 men); 8 subjects without syncope and a negative tilt test result served as control subjects (mean age 49+/-10 years, 5 men). Twenty-five milligrams of clomipramine was administered intravenously within 15 minutes, and blood samples were taken at 0, 15, 30, 45, and 60 minutes. Two days later, a tilt test was performed at 60 degrees for 30 minutes and blood samples were taken at 0, 10, 20, and 30 minutes. During the clomipramine challenge, plasma prolactin levels increased in both groups. The levels at 30 minutes were higher in the patient group compared with the control group (17.3+/-7.2 vs 9.3+/-7.6 ng/mL, P=0.05). Similar results were observed for cortisol at 30 minutes (172+/-15 vs 118+/-21 ng/mL P=0. 04) and at 45 minutes (189+/-20 vs 116+/-23 ng/mL, P=0.03). The tilt test was positive in 8 (67%) out of 12 of the patient group and negative in all control subjects. In the samples taken during the tilt test, significant increases in prolactin and cortisol were observed only in the subjects with positive tilt test results.

CONCLUSIONS

Patients with a history of neurocardiogenic syncope show a higher responsiveness of the central serotonergic system to clomipramine challenge. The results support the view that central serotonergic mechanisms are involved in the pathophysiology of the syndrome.

Clinical utility of the selective serotonin reuptake inhibitors in the spectrum of anxiety

The selective serotonin reuptake inhibitors (SSRIs) are now being employed in the treatment of the full spectrum of anxiety disorders. In comparative trials, the SSRIs are proving to be equal or superior in efficacy to traditional antianxiety medications. Due to their favorable side effect profile, safety, and tolerability, they are rapidly replacing older agents in the treatment of anxiety. Neuroanatomical pathways that may be important in the antianxiety effect of the SSRIs are outline and discussed, followed by a review of the clinical evidence supporting the efficacy of this class of medications in the treatment of anxiety disorders.

Intravenous clomipramine challenge in obsessive-compulsive disorder: predicting response to oral therapy at eight weeks

BACKGROUND

Challenge with intravenous clomipramine (CMI) is serotonin selective and has been reported to transiently exacerbate symptoms in obsessive-compulsive disorder (OCD) patients, and to predict subsequent response to oral CMI therapy.

METHODS

We administered CMI (12.5 mg, i.v.) to medication free OCD patients (N = 29) and normal controls (N = 22) to characterize neurohormonal response. A subset of OCD patients (26/29), was then treated with either pulse load i.v. or oral CMI followed by 8 weeks of oral CMI therapy.

RESULTS

In response to CMI challenge, OCD patients exhibit blunted cortisol and exaggerated growth hormone response relative to normal controls. OCD patients differ from controls in "sadness" ratings, with control exhibiting increased dysphoria in response to CMI. Growth hormone response to CMI challenge predicts treatment response (> or = 25% decreases YBOCS from baseline) to oral CMI at 8 weeks.

CONCLUSIONS

Growth hormone abnormalities associated with OCD in response to CMI challenge differentiates nonresponders after 8 weeks of oral CMI treatment from responders.

Serotonin and panic

BACKGROUND

Tricyclic (TCA) and monoamine oxidase inhibitor (MAOI) antidepressants are effective in the treatment of panic disorder. Two selective serotonin reuptake inhibitors (SSRIs) have also been licensed in the UK for this indication and studies with three other SSRIs have recently been completed. These provide further evidence for the role of serotonin in panic.

METHOD

Review of clinical, animal and laboratory studies.

RESULTS

SSRIs have been shown to be effective in the treatment of panic disorder. The reported rates of improvement of 60-70% of patients taking SSRIs are similar to those seen with TCAs and greater than placebo. Other serotonergic agents do not appear to be effective. Animal work and human studies including measures of 5-HT in plasma, cerebrospinal fluid and platelets, challenge paradigms and tryptophan depletion show that the relationship between 5-HT and anxiety is complex.

CONCLUSION

Clinical trials have shown that of all the serotonergic agents only the SSRIs are effective in panic disorder. They are as beneficial as the TCAs and seem to be better tolerated which may be particularly significant in view of the chronic nature of the condition. Serotonin plays a role in panic disorder and serotonergic dysfunction, however the results and evidence do not fit one theory alone. It is also likely that different brain regions and 5-HT receptors are involved in specific ways.