Cross-disorder genome-wide analyses suggest a complex genetic relationship between Tourette's syndrome and OCD

OBJECTIVE

Obsessive-compulsive disorder (OCD) and Tourette's syndrome are highly heritable neurodevelopmental disorders that are thought to share genetic risk factors. However, the identification of definitive susceptibility genes for these etiologically complex disorders remains elusive. The authors report a combined genome-wide association study (GWAS) of Tourette's syndrome and OCD.

METHOD

The authors conducted a GWAS in 2,723 cases (1,310 with OCD, 834 with Tourette's syndrome, 579 with OCD plus Tourette's syndrome/chronic tics), 5,667 ancestry-matched controls, and 290 OCD parent-child trios. GWAS summary statistics were examined for enrichment of functional variants associated with gene expression levels in brain regions. Polygenic score analyses were conducted to investigate the genetic architecture within and across the two disorders.

RESULTS

Although no individual single-nucleotide polymorphisms (SNPs) achieved genome-wide significance, the GWAS signals were enriched for SNPs strongly associated with variations in brain gene expression levels (expression quantitative loci, or eQTLs), suggesting the presence of true functional variants that contribute to risk of these disorders. Polygenic score analyses identified a significant polygenic component for OCD (p=2×10(-4)), predicting 3.2% of the phenotypic variance in an independent data set. In contrast, Tourette's syndrome had a smaller, nonsignificant polygenic component, predicting only 0.6% of the phenotypic variance (p=0.06). No significant polygenic signal was detected across the two disorders, although the sample is likely underpowered to detect a modest shared signal. Furthermore, the OCD polygenic signal was significantly attenuated when cases with both OCD and co-occurring Tourette's syndrome/chronic tics were included in the analysis (p=0.01).

CONCLUSIONS

Previous work has shown that Tourette's syndrome and OCD have some degree of shared genetic variation. However, the data from this study suggest that there are also distinct components to the genetic architectures of these two disorders. Furthermore, OCD with co-occurring Tourette's syndrome/chronic tics may have different underlying genetic susceptibility compared with OCD alone.

Obstructive sleep apnea in combat-related posttraumatic stress disorder: a controlled polysomnography study

BACKGROUND

Obstructive sleep apnea (OSA) may be highly prevalent in posttraumatic stress disorder (PTSD) and may exacerbate PTSD complaints.

OBJECTIVE

Our objective was to determine whether the prevalence of OSA was high in a sample of Dutch veterans with PTSD as compared to age- and trauma-matched controls, and whether OSA was associated with more severe PTSD complaints.

METHODS

We determined the apnea hypopnea indices (AHI) with polysomnographic registrations in 20 veterans with PTSD, 24 veterans without PTSD, and 17 healthy controls. PTSD severity and nightmare complaints were assessed with the Clinician-Administered PTSD Scale (CAPS).

RESULTS

The prevalence of an AHI>10 was 29% in PTSD, 21% in trauma controls, and 29% in healthy controls (χ(2)= 0.60, df=2, p=n.s.). The mean CAPS score in patients with OSA (n=6) was significantly higher than in patients without OSA (p<0.05), while nightmare severity was similar in PTSD patients with OSA as compared to PTSD patients without OSA (p=n.s.). Furthermore, there was a significant correlation between AHI and CAPS score in PTSD patients (r=0.46, p<0.05, df=14).

CONCLUSIONS

Our results indicate that PTSD is not necessarily associated with a higher prevalence of OSA. However, PTSD severity was related to OSA, which may possibly mean that comorbid OSA leads to an increase in PTSD complaints. However, future research should indicate whether OSA exerts a negative influence on PTSD, and treatment of OSA alleviates PTSD symptoms.

The effect of olanzapine treatment on monoamine metabolite concentrations in the cerebrospinal fluid of schizophrenic patients

The mechanism of action of both typical antipsychotics and the atypical antipsychotic, clozapine, may be related to the (changing) interaction of dopamine and serotonin in schizophrenia. This study examined the effect of olanzapine in schizophrenic patients on cerebrospinal fluid (CSF) metabolites of dopamine (homovanillic acid, HVA) and serotonin (5-hydroxyindoleacetic acid, 5-HIAA). Twenty-three male schizophrenic patients, who were drug-free for at least 2 weeks (mean drug-free period of 35 days +/- 43; median 16 days), underwent a lumbar puncture (LP). Patients were subsequently treated with olanzapine 10 mg/day for 6 weeks, after which the LP was repeated. CSF was assayed for HVA and 5-HIAA concentrations. Psychiatric symptoms were rated once a week. Olanzapine significantly increased HVA concentrations and the HVA/5-HIAA ratio while 5-HIAA concentrations were not altered. These changes did not significantly correlate with treatment response. A negative correlation was found between HVA concentrations and negative symptoms after olanzapine treatment. In conclusion, olanzapine treatment increases HVA concentrations and the HVA/5-HIAA ratio in CSF of schizophrenic patients, but these changes are unrelated to its clinical efficacy.

Characteristics of patients with social phobia and their treatment in specialized clinics for anxiety disorders in the Netherlands

BACKGROUND

Social phobia frequently occurs in the general population but is probably underreported due to comorbid disorders which mask the social phobia. Another reason might be that patients do not consult their general pratitioner due to embarrassment or an estimation of their condition. There are several treatments available for social phobia, but not enough is known about the efficacy of the different treatments strategies.

METHODS

A retrospective, medical record-based study was carried out in four outpatient clinics specializing in treatment of anxiety disorders to investigate the characteristics of 64 patients with a DSM-IV axis diagnosis of social phobia who seeked help for their problems. Therapies for social phobia within these clinics and differences between these clinics were evaluated.

RESULTS

Men with a high educational level tended to seek more help and comorbid disorders tended to cause more impairment in functioning. Further, there is a large delay between onset and therapy attendance (mean 14 years). Finally, there was consistency in the treatment of social phobia in these four clinics which consisted of cognitive behavioral therapy and/or medication.

LIMITATIONS

The study is retrospective and based on medical records which means there was no objective measurement of the effectiveness of the therapies.

CONCLUSIONS

Seventy-five percent of patients improved after treatment independent of the kind of therapy, the occurrence of comorbid disorders and the type of social phobia.

[Inadequate pharmacotherapy in patients with obsessive-compulsive disorder]

OBJECTIVE

To determine the adequacy of drug treatment for patients with obsessive compulsive disorder (OCD).

DESIGN

Retrospective.

METHOD

One hundred and fifty outpatients with OCD, admitted at the University Medical Centre in Utrecht, the Netherlands, were evaluated for severity as measured with the 'Yale-Brown obsessive compulsive scale' (Y-BOCS).

RESULTS

At the intake, 35% of the patients used no medication, 58% used an antidepressant, less than 1% an antipsychotic and 6% a benzodiazepine. The average active dose was taken by 12% of the patients, 5% took the maximum dosage and 41% too low a dosage. Consequently, 6 out of the 10 patients used the correct medication (antidepressant) and less than 20% used a sufficiently high dosage. Of the patients, 38% had never previously taken antidepressants, 31% had previously used one antidepressant, 17% two different antidepressants and 12% at least three different antidepressants; 13% had taken the antidepressant at the highest dosage, 18% at the average active dosage and 31% at too low (thus ineffective) a dosage. This means that from a pharmacotherapeutic viewpoint not more than 1 in 8 patients had had an adequate treatment history.

CONCLUSION

The results of this study show that only 1 in 8 OCD patients were treated appropriately.

Anxiety disorders: a review of tricyclic antidepressants and selective serotonin reuptake inhibitors

OBJECTIVE

Anxiety disorders are the most common mental health disorders. While the older tricylic antidepressants (TCAs) are efficacious in the treatment of many anxiety disorders, recent studies with fluoxetine and other selective serotonin reuptake inhibitors (SSRIs) have emphasized the role of serotonin in the aetiology of these conditions.

METHOD

We reviewed the efficacy, safety and tolerability of TCAs and SSRIs in the treatment of the most common anxiety disorders, specifically, panic disorder, obsessive-compulsive disorder, post-traumatic stress disorder, social phobia and generalized anxiety disorder.

RESULTS

Both the TCA and SSRI antidepressants are effective in treating a wide variety of anxiety disorders. SSRIs, due to their greater safety and tolerability, should be the preferred choices in treating anxiety disorders in those instances where TCAs and SSRIs are considered equally effective. In the cases of OCD and social phobia, SSRIs are almost always preferable given that the TCAs do not appear effective in these disorders.

CONCLUSION

Further research is needed on the naturalistic long-term use of the TCAs and SSRIs in the treatment of anxiety disorders.

The bovine protein alpha-lactalbumin increases the plasma ratio of tryptophan to the other large neutral amino acids, and in vulnerable subjects raises brain serotonin activity, reduces cortisol concentration, and improves mood under stress

BACKGROUND

Increased brain serotonin may improve the ability to cope with stress, whereas a decline in serotonin activity is involved in depressive mood. The uptake of the serotonin precursor, tryptophan, into the brain is dependent on nutrients that influence the cerebral availability of tryptophan via a change in the ratio of plasma tryptophan to the sum of the other large neutral amino acids (Trp-LNAA ratio). Therefore, a diet-induced increase in tryptophan availability may increase brain serotonin synthesis and improve coping and mood, particularly in stress-vulnerable subjects.

OBJECTIVE

We tested whether alpha-lactalbumin, a whey protein with a high tryptophan content, may increase the plasma Trp-LNAA ratio and reduce depressive mood and cortisol concentrations in stress-vulnerable subjects under acute stress.

DESIGN

Twenty-nine highly stress-vulnerable subjects and 29 relatively stress-invulnerable subjects participated in a double-blind, placebo-controlled study. Subjects were exposed to experimental stress after the intake of a diet enriched with either alpha-lactalbumin or sodium-caseinate. Diet-induced changes in the plasma Trp-LNAA ratio and prolactin were measured. Changes in mood, pulse rate, skin conductance, and cortisol concentrations were assessed before and after the stressor.

RESULTS

The plasma Trp-LNAA ratio was 48% higher after the alpha-lactalbumin diet than after the casein diet (P = 0.0001). In stress-vulnerable subjects this was accompanied by higher prolactin concentrations (P = 0.001), a decrease in cortisol (P = 0.036), and reduced depressive feelings (P = 0.007) under stress.

CONCLUSIONS

Consumption of a dietary protein enriched in tryptophan increased the plasma Trp-LNAA ratio and, in stress-vulnerable subjects, improved coping ability, probably through alterations in brain serotonin.

Serotonergic blunting to meta-chlorophenylpiperazine (m-CPP) highly correlates with sustained childhood abuse in impulsive and autoaggressive female borderline patients

BACKGROUND

Disturbances of affect, impulse regulation, and autoaggressive behavior, which are all said to be related to an altered function of the central serotonergic (5-HT) system, are prominent features of borderline personality disorder (BPD). A high coincidence of childhood physical and sexual abuse is reported in these patients. Animal studies indicate that early, sustained stress correlates with a dysfunctional central 5-HT system. Therefore, we hypothesize that sustained traumatic stress in childhood affects the responsivity of the postsynaptic serotonergic system of traumatized BPD patients.

METHODS

Following Axis I, Axis II, and trauma assessment, a neuroendocrine challenge test was performed with the postsynaptic serotonergic agonist meta-chlorophenylpiperazine (m-CPP) in 12 impulsive and autoaggressive female patients with BPD and 9 matched healthy volunteers.

RESULTS

The cortisol and prolactin responses to the m-CPP challenge in BPD patients were significantly lower compared to those in controls. Within the group of patients with BPD, the net prolactin response showed a high inverse correlation with the frequency of the physical (r = -.77) and sexual abuse (r = -.60).

CONCLUSIONS

Our data suggest that severe and sustained traumatic stress in childhood affects the 5-HT system and especially 5-HT(1A) receptors. This finding confirms the data from animal research. The blunted prolactin response to m-CPP appears to be the result of severe traumatization and independent of the BPD diagnosis.

Pharmacology of antidepressants: selectivity or multiplicity?

The understanding of mechanisms of antidepressant action has evolved over time. The strong antidepressant activity of the tricyclic antidepressants (TCAs) has supported the role of both norepinephrine and serotonin (5-HT) in depression and the mechanism involved in antidepressant action. The next generation of antidepressants included the selective serotonin reuptake inhibitors (SSRIs), further supporting the role of serotonin, while the selective norepinephrine reuptake inhibitors such as maprotiline and reboxetine underlined the relevance of norepinephrine. These developments suggest that either facilitation of serotonin or norepinephrine or both may lead to an antidepressant response. The next step was the development of mixed serotonin-norepinephrine reuptake inhibitors (SNRIs), exemplified by venlafaxine and milnacipran. As with the TCAs, the antidepressant activity of SNRIs is based on inhibition of norepinephrine and serotonin reuptake, but unlike TCAs they do not have anticholinergic, antihistaminergic, and cardiotoxic effects. Although norepinephrine is known to stimulate serotonin cell firing rate via the alpha1-adrenoceptors, norepinephrine and serotonin have independent antidepressant actions. The latest development has been the introduction of the noradrenergic and specific serotonergic antidepressant mirtazapine. Its antidepressant effect appears to be related to dual enhancement of central noradrenergic and serotonergic neurotransmission by blockade of alpha2-adrenoceptors. In addition, mirtazapine directly blocks 5-HT2 and 5-HT3 receptors, which may account for its anxiolytic and sleep-improving properties as well as its lack of adverse events that are typical of SSRIs.

Facing the challenge of social anxiety disorder

Social anxiety disorder is at serious and prevalent disorder that leads to significant disability in the social and professional lives of patients. It is a chronic condition that frequently coexists with other psychiatric conditions such as depression or alcoholism. Pharmacotherapy with benzodiazepines, monoamine oxidase inhibitors and selective serotonin reuptake inhibitors (SSRIs) has been assessed. Alprazolam has modest efficacy, while a more robust response to clonazepam has been reported. Benzodiazepines, however, are not suitable for long-term treatment of a chronic condition such as social anxiety disorder and are ineffective against comorbid depression. Phenelzine has demonstrated efficacy but the need for dietary restrictions has limited its use. Conflicting results have been reported in placebo-controlled trials for moclobemide, with two studies showing moclobemide to be more effective than placebo while recent trials have reported less robust results. Based on clinical evidence, SSRIs are the first-line treatment in social anxiety disorder. The most extensive database for the treatment of social anxiety disorder exists for the SSRI, paroxetine. Three large multicentre, placebo-controlled, trials have been completed. In all three studies, a significantly greater proportion of patients responded to paroxetine treatment compared with placebo. Paroxetine is currently the only SSRI licensed for use in this condition.

Sumatriptan (5-HT1D receptor agonist) does not exacerbate symptoms in obsessive compulsive disorder

The non-selective serotonin (5-HT) receptor agonist meta-chlorophenylpiperazine (mCPP) has been reported to elicit symptoms in patients with obsessive compulsive disorder (OCD). MK-212, another non-selective 5-HT receptor agonist, does not seem to induce obsessive compulsive symptoms in OCD patients. The major pharmacological difference between mCPP and MK-212 is their affinity for the 5-HT(ID) receptor. The aim of this study was to explore the role of the 5-HT(ID) receptor in the pathophysiology of OCD, by using a challenge paradigm with the selective 5-HT(ID) receptor agonist sumatriptan (Imigran). A randomized, double-blind, placebo-controlled crossover challenge with sumatriptan (100 mg PO) was performed in 15 OCD patients. Neither the obsessive compulsive symptoms nor mood or anxiety symptoms changed significantly following sumatriptan administration as compared to placebo. Sumatriptan did induce a significant increase in plasma growth hormone (GH) levels. In the present study, no indication were found for the role of the 5-HT(ID) receptor in the pathophysiology of OCD. It should be noted, however, that sumatriptan does not readily pass the blood-brain barrier. Selective 5-HT(ID) receptors with better brain penetrating properties may shed more light on the role of this 5-HT receptor subtype in OCD.

The nature of social anxiety disorder

The essential feature of social anxiety disorder (social phobia) is a fear of scrutiny by other people in social or performance situations. The level of anxiety experienced by the person with social anxiety disorder is excessive, and results in substantial impairment in the sufferer's social, family, and professional life. Three distinct subtypes of the disorder have been identified: generalized social anxiety disorder, in which the individual fears a multitude of social situations; nongeneralized social anxiety disorder, in which only 2 or 3 situations are feared; and public-speaking phobia. Results from a number of studies suggest that these subtypes of social anxiety disorder may represent distinct clinical syndromes, with the generalized subtype producing the most severe disability. Despite the prevalence of social anxiety disorder and the disability it causes, this condition remains underdiagnosed, and thus undertreated, by clinicians. This review discusses the barriers that prevent people who have this disorder from seeking help, and the steps that clinicians can take to aid their recognition and treatment of the disorder. It is only by effective diagnosis and treatment that the burden of social anxiety disorder will be lifted, allowing patients to resume a normal life.

Consensus statement on social anxiety disorder from the International Consensus Group on Depression and Anxiety

OBJECTIVE

The goal of this consensus statement is to provide primary care clinicians with a better understanding of management issues in social anxiety disorder (social phobia) and guide clinical practice with recommendations for appropriate pharmacotherapy.

PARTICIPANTS

The 4 members of the International Consensus Group on Depression and Anxiety were James C. Ballenger (chair), Jonathan R. T. Davidson, Yves Lecrubier, and David J. Nutt. Other faculty invited by the chair were Julio Bobes, Deborah C. Beidel, Yukata Ono, and Herman G. M. Westenberg.

EVIDENCE

The consensus statement is based on the 7 review papers published in this supplement and on the scientific literature relevant to the issues reviewed in these papers.

CONSENSUS PROCESS

The group met over a 2-day period. On day 1, the group discussed each review paper, and the chair identified key issues for further debate. On day 2, the group discussed these issues to arrive at a consensus view. After the group meetings, the consensus statement was drafted by the chair and approved by all attendees.

CONCLUSIONS

The consensus statement underlines the importance of recognizing social anxiety disorder and provides recommendations on how it may be distinguished from other anxiety disorders. It proposes definitions for response and remission and considers appropriate management strategies. Selective serotonin reuptake inhibitors are recommended as first-line therapy, and effective treatment should be continued for at least 12 months. Long-term treatment is indicated if symptoms are unresolved, the patient has a comorbid condition or a history of relapse, or there was an early onset of the disorder.

Effects of meta-chlorophenylpiperazine on cerebral blood flow in obsessive-compulsive disorder and controls

BACKGROUND

A number of studies have shown that the serotonin receptor agonist meta-chlorophenylpiperazine (mCPP) can exacerbate symptoms in patients with obsessive-compulsive disorder (OCD). The aim of the present study was to study the effect of this compound on regional cerebral blood flow (rCBF) in patients and controls.

METHODS

Seven OCD patients and 8 healthy controls were randomly allocated to a double-blind challenge study with mCPP (0.5 mg/kg orally). rCBF was measured by 99m-Tc-hexamethyl-propyleneamineoxime single photon emission computed tomography.

RESULTS

mCPP did not induce OCD symptoms in patients, but caused a significant decrease in rCBF in OCD patients, but not in controls. The decrease was seen in the reference regions cerebellum and whole brain, and in the frontal cortex, caudate nucleus, putamen, and thalamus.

CONCLUSIONS

The effect of mCPP on the reference regions in patients posed methodological problems in the normalization methods. A possible role of the cerebellum in OCD is discussed.

Serotonin syndrome after challenge with the 5-HT agonist meta-chlorophenylpiperazine

meta-Chlorophenylpiperazine (mCPP) is a non-selective 5-HT-receptor agonist/antagonist that is used extensively in psychiatry to assess central serotonergic function. We report on three patients who developed symptoms of the serotonin syndrome when they participated in an mCPP (0.5 mg/kg body weight p.o.) challenge test as part of a research protocol. They had relatively high plasma mCPP concentrations. The syndrome did not occur in normal volunteers who had comparable plasma concentrations of mCPP. Investigators should be aware of the possible occurrence of the serotonin syndrome after a single oral dose of mCPP.

Postsynaptic 5-HT1A receptors mediate 5-hydroxytryptamine release in the amygdala through a feedback to the caudal linear raphe

Using brain microdialysis, it was demonstrated that the release of 5-hydroxytryptamine (5-HT) in the central nucleus of the amygdala is under inhibitory control of somatodendritic and postsynaptic 5-HT1A receptors. Systemic administration of flesinoxan, a selective 5-HT1A receptor agonist, significantly reduced the extracellular levels of 5-HT in the central nucleus of the amygdala. This effect could be completely antagonized by the 5-HT1A receptor antagonist N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)-N-(2-pyridyl)cyclohexane carboxamine trihydrochloride (WAY 100635). Local administration of these compounds by reversed microdialysis into the raphe nuclei revealed that extracellular 5-HT levels in the central nucleus of the amygdala can be regulated through 5-HT1A receptors in the caudal linear raphe nucleus, but not in the dorsal and median raphe nuclei. Interestingly, administration of flesinoxan into the central nucleus of the amygdala also decreased dialysate 5-HT levels both locally and in the caudal linear raphe nucleus. The former effect could be blocked by pretreatment with WAY 100635 when applied into the central nucleus of the amygdala, but not when applied into the caudal linear raphe nucleus. These data provide circumstantial evidence for the existence of a 5-HT1A receptor mediated feedback loop from the central nucleus of the amygdala to the caudal linear raphe nucleus.

Clinical effects of buspirone in social phobia: a double-blind placebo-controlled study

BACKGROUND

The results of open pilot studies suggest that the serotonin-1A (5-HT1A) receptor agonist buspirone might be effective in social phobia.

METHOD

In the present study, the efficacy of buspirone was investigated in patients with social phobia using a 12-week double-blind placebo-controlled design. Thirty social phobic patients (DSM-IV) were treated with either buspirone 30 mg daily or placebo. Efficacy of treatment was measured using the Social Phobia Scale (subscores anxiety and avoidance) and the Hamilton Rating Scale for Anxiety.

RESULTS

Taking a reduction of 50% or more on the Social Phobia Scale as a criterion for clinically relevant improvement, only 1 patient on buspirone and 1 on placebo were classified as responder to treatment. A subjective and clinically relevant improvement was reported by 4 patients (27%) on buspirone and 2 patients (13%) on placebo. There were no statistically significant differences between buspirone and placebo on any of the outcome measures. Generally speaking, buspirone was well tolerated.

CONCLUSION

The results of the study do not support the results of open studies, in which a reduction of social anxiety and social avoidance was reported in patients with social phobia treated with buspirone.

Effect of the selective serotonin reuptake inhibitor fluvoxamine on CCK-4 induced panic attacks

Data from animal studies suggest a functional relationship between the cholecystokinin-ergic (CCK) and the serotonergic (5-HT) system. There is increasing evidence that the cholecystokinin-4 (CCK4) challenge test could be a valid experimental model for panic attacks in man. The aim of the present study is twofold; 1) to validate this model further and 2) to shed more light on the putative CCK/5-HT interaction. To this end, we studied the effect of the selective serotonin reuptake inhibitor (SSRI) fluvoxamine on CCK4-induced panic attacks. Twenty-six panic disorder (PD) patients received, before and after a double blind 8-week treatment period with fluvoxamine (n = 17) or placebo (n = 9), a single blind bolus injection with 50 micrograms CCK4. Treatment with fluvoxamine (150 mg daily) significantly decreased the sensitivity of PD patients for CCK4 while placebo was without effect. Of the patients who responded to treatment, 83% no longer experienced a panic attack when rechallenged with CCK4, whereas in the non-responders group this was only 28%. In the fluvoxamine group the treatment response evaluated by the Hamilton Anxiety Scale (HAS) showed a statistically significant treatment effect. The results of this study strengthen the validity of the CCK4 test as an experimental human model for panic attacks and yield evidence supporting the hypothesis that both CCK and serotonin are implicated in the regulation of anxiety.

The cholecystokinin-B receptor antagonist CI-988 failed to affect CCK-4 induced symptoms in panic disorder patients

The effects of the cholecystokinin-B (CCK-B) receptor antagonist CI-988 on symptoms elicited by the cholecystokinin tetrapeptide (CCK4) were studied in DSM-IIIR patients with panic disorder. The study employed a double-blind, two-period incomplete block design. Patients (n = 14) received two different dosages of CI-988 (50 mg or 100 mg) or placebo 2 h prior to an IV bolus injection of CCK4 (20 micrograms) on two separate occasions. The primary efficacy parameter was the total intensity score on the Panic Symptoms Scale (PSS). Secondary parameters were the number of panic symptoms, time to and occurrence of the first panic symptoms, duration of symptoms, intensity of apprehension and the percentage of patients who did not have a panic attack. The PSS failed to show a statistically significant treatment effect on any of these outcome measures. The average panic rate was 50%, 14.3% and 37.5% after placebo, 50 and 100 mg CI-988, respectively. The differences in panic rate were not statistically significant. The results of this study suggest that CI-988 in doses up to 100 mg is not effective in reducing symptoms of panic anxiety induced by CCK4.

Cholecystokinin in anxiety

Cholecystokinin (CCK) plays an important role in both the alimentary tract and the central nervous system (CNS). At present it seems to be the most abundant neuropeptide in the CNS. This paper reviews the CCK neuronal system and its interactions with gamma-aminobutyric acid (GABA) and serotonin (5-hydroxytryptamine; 5-HT). In addition, its putative role in anxiety will be discussed on the basis of animal data and studies in healthy volunteers and panic disorder patients. According to these investigations, the CCK4 challenge test fulfills most criteria for an ideal panicogenic agent and evidence has been found that CCKB receptor antagonists might possess anxiolytic properties in man.

MHPG and heart rate as correlates of nonresponse to drug therapy in panic disorder patients. A preliminary report

Little is known about biological predictors of treatment response in panic disorder (PD). In the present study heart rate, blood pressure, plasma cortisol and plasma MHPG were investigated at baseline in a sample of 44 PD patients as possible predictors for nonresponse to treatment. We used a strict definition of nonresponse to find patients who did not respond at all after 12 weeks of treatment with brofaromine or fluvoxamine. Patients were considered nonresponders when they fulfilled two criteria: they did not show a 50% reduction of agoraphobic avoidance and they still experienced panic attacks at endpoint. The variables that differed significantly between the groups were used to predict nonresponse to drug therapy. Using this strict definition of nonresponse, 15 patients (32.6%) were considered nonresponders. These patients were characterised by a higher plasma MHPG concentration and a higher heart rate at baseline. These variables were subsequently used to predict nonresponse.

Developments in the drug treatment of panic disorder: what is the place of the selective serotonin reuptake inhibitors?

Panic disorder is becoming better recognised and understood as a chronic, debilitating but treatable condition. Drug treatment options shown by adequate research to be beneficial in this condition include mainly the benzodiazepine alprazolam, the tricyclic antidepressants (TCAs) imipramine and clomipramine, the monoamine oxidase inhibitor (MAOI) phenelzine, and the newer selective serotonin reuptake inhibitors (SSRIs) fluvoxamine and paroxetine. Alprazolam, although approved for use in panic disorder in the US and very widely used, is associated with a risk of dependence and withdrawal syndromes. Given that depression frequently occurs as a comorbid condition with panic disorder the use of antidepressants is a logical choice. Among the antidepressants, MAOIs are little-used in panic disorder, mainly because of their potential for precipitating hypertensive crises if tyramine is ingested. TCAs are widely used and are effective but they are associated with initial activation, or 'jitteriness', have a 4-6-week time lag before onset of beneficial effect and produce troublesome side effects in a high proportion of patients, particularly during long-term use. TCAs are also cardiotoxic in overdosage, and panic disorder patients with comorbid depression are at high risk of attempted suicide. Serotonin dysregulation has been implicated in the pathogenesis of anxiety disorders in general, and panic disorder in particular. Among the TCAs, those with an effect on serotonin reuptake are most effective in panic disorder. SSRIs are specifically active on serotonin reuptake and do not have anticholinergic effects or act on the noradrenergic system. There is a clear pharmacological rationale for believing that SSRIs should be as effective as TCAs in panic disorder and better tolerated. Accumulating clinical research evidence supports this hypothesis. Further comparative studies with standard agents and additional long-term studies to support the initial long-term data with paroxetine are needed to confirm SSRIs as drug treatment of choice in panic disorder.

Effects of the 5-HT1A receptor agonist flesinoxan in panic disorder

The effects of flesinoxan, a potent and selective 5-HT1A agonist, were studied in two pilot studies in panic disorder patients to explore the role of 5-HT1A receptors in the mechanism of action of antipanic agents. This paper reports on the results of these two studies with flesinoxan. In study I, using a single-blind crossover design, five patients were treated for 1 week with placebo, 4 weeks with flesinoxan (up to 2.4 mg per day), and 2 weeks with placebo. In study II, 15 patients were enrolled in a double-blind, three-armed study with placebo and two dosages of flesinoxan. After a single-blind placebo run-in phase of 1 week, patients were treated for 8 weeks with placebo, 0.6 or 1.2 mg/day flesinoxan. In pilot study I patients' condition worsened during the 4-week flesinoxan treatment period. Anxiety was frequently reported as an adverse event. Symptoms returned to the pre-treatment level during the 2-week placebo washout period. In pilot study II, no treatment effects in either group were observed. Anxiety as an adverse event was less prominent than in the first pilot study. A lowering of mood was seen in some patients. The sample sizes of these two pilot studies are too small to draw firm conclusions on the efficacy of flesinoxan in panic disorder, but the present data are not encouraging in this respect. The worsening of symptoms seen with the highest dose of flesinoxan is intriguing and might give a clue to the understanding of the mechanism underlying similar effects seen with antidepressants in panic disorder patients.

Pentagastrin has panic-inducing properties in obsessive compulsive disorder

The effects of the CCKB-receptor agonist pentagastrin, a synthetic analogue of the cholecystokinin tetrapeptide (CCK-4), were studied in seven patients suffering from obsessive compulsive disorder (OCD) and seven healthy controls. All subjects were challenged with an IV dose of 0.6 micrograms/kg pentagastrin or placebo under double blind placebo controlled conditions, on two separate occasions, with a minimum interval of 1 week. Six (86%) out of seven OCD patients experienced a panic-like reaction after pentagastrin administration, against only two (29%) in the control group. These differences failed to reach statistical significance, probably due to the small sample size. No increases were observed in obsessions or compulsive behaviors as assessed with the Yale-Brown Obsessive Compulsive Challenge Scale, neither in the pentagastrin, nor in the placebo condition. These findings suggest that pentagastrin has panic-inducing properties in OCD patients, without affecting the core symptoms. The panic-inducing properties of pentagastrin are not specific for panic disorder patients, which might be indicative of a common neurobiological dysfunction in panic disorder and OCD at the level of CCK-B receptors.

The panic-inducing properties of the cholecystokinin tetrapeptide CCK4 in patients with panic disorder

We studied the effect of the cholecystokinin tetrapeptide (CCK4), a potent CCKB antagonist, in patients with panic disorder. Two different dosages (25 and 50 micrograms) of CCK4 and saline were tested in 12 patients who were randomly allocated to 2 of the 3 possible treatment groups. Patients were tested on 2 separate occasions, 1 week apart, using an unbalanced single-blind incomplete block design. A total of 24 intravenous injections were carried out. The panic rate with 25 micrograms CCK was 44% (4/9) and 71% (5/7) with 50 micrograms. None of the patients panicked with saline (0/8). Patients' symptom responses were very similar to their spontaneous panic attacks. Taking the Panic Symptom Scale (PSS) as outcome variable, we found that CCK4 provoked symptoms of panic in a dose-dependent fashion. The behavioral response to CCK4 was not accompanied by activation of the hypothalamic-pituitary-adrenal (HPA) axis as measured by the prolactin and cortisol responses. Moreover, CCK4-induced panic symptoms were not correlated with plasma increases in the principal noradrenergic metabolite, 3-methoxy-4-hydroxy-phenylglycol (MHPG), suggesting that activation of the locus coeruleus may not be critical for CCK4-induced panic.

A double-blind comparative study of brofaromine and fluvoxamine in outpatients with panic disorder

Previous studies have shown that both selective serotonin reuptake inhibitors (SSRIs) and monoamine oxidase inhibitors (MAOIs) are effective in the treatment of panic disorders (PD). In this study, the SSRI fluvoxamine (Fluv) was compared with the MAO-A-I brofaromine (Brof). Thirty patients with the diagnosis of PD with or without agoraphobia were treated with either Fluv or Brof (150 mg daily) in a double-blind design. After 12 weeks of treatment, 93% of the Brof group and 87% of the Fluv group considered themselves much or very much improved. Taking a reduction in the Hamilton Rating Scale for Anxiety score of 50% or more, 33% of the Fluv patients and 47% of the Brof patients were responders to treatment. After an increase in anxiety in the 1st week, which was more severe in Fluv-treated patients than for Brof, a clinically relevant decrease in anxiety symptoms and reduction in panic attacks and avoidance behavior was observed. There was no significant difference between the treatment groups. The most prominent side effects were middle-sleep disturbance (Brof), tiredness (Fluv), and nausea after taking the medication (Brof and Fluv). During a double-blind follow-up period of another 12 weeks, a further improvement was found in both treatment groups without significant differences between the two groups. The selective and reversible MAO-A-I brofaromine and the SSRI fluvoxamine are equally effective in the treatment of PD. Both compounds lead to a reduction in the number of panic attacks and a subsequent reduction in agoraphobic avoidance.

Responders and non-responders to drug treatment in social phobia: differences at baseline and prediction of response

Differences between responders and non-responders to drug therapy were investigated in social phobia. Two previously published studies were pooled to obtain data of 30 patients who were treated for 12 weeks with brofaromine or fluvoxamine. Four criterion variables were used to divide patients in responders and non-responders. Depending on the criterion variable up to 72% of the patients were regarded as responders. Non-responders differed from responders in that they had a higher heart rate and a higher blood pressure. They were also characterized by higher scores on several psychometric scales, indicative of illness severity.

Flesinoxan dose-dependently reduces extracellular 5-hydroxytryptamine (5-HT) in rat median raphe and dorsal hippocampus through activation of 5-HT1A receptors

The effects of systemic administration of the serotonin (5-hydroxytryptamine) 5-HT1A receptor agonists flesinoxan and 8-hydroxy-2-(di-n-propylamino)tetralin on extracellular 5-HT were measured using microdialysis probes in both median raphe nucleus and dorsal hippocampus. Both 5-HT1A agonists dose-dependently decreased dialysate 5-HT levels from both brain regions. The effects of flesinoxan in the median raphe (0.3 mg/kg) and dorsal hippocampus (1.0 mg/kg) could be blocked by the 5-HT1A receptor antagonist N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridyl)cyclohexane carboxamide trihydrochloride (WAY 100,635) at a dose of 0.05 mg/kg s.c. The antagonist itself had no effect at this dosage. Local perfusion of flesinoxan for 30 min through the dialysis probe into the median raphe region at concentrations of 20, 100, and 1,000 nM resulted in a significant decrease in dialysate 5-HT content from both regions. The effect of 100 nM flesinoxan could be blocked by coperfusion of 1,000 nM WAY 100,635. The data indicate that flesinoxan is a potent 5-HT1A receptor agonist and also support the notion that somatodendritic 5-HT1A autoreceptors regulate both terminal and somatodendritic 5-HT release.

Behavioral, neuroendocrine and biochemical effects of different doses of 5-HTP in panic disorder

To investigate the role of serotonin (5-HT) in the pathophysiology of panic disorder (PD) a challenge test with L-5-hydroxytryptophan (5-HTP) was conducted. Seven patients suffering from PD and seven healthy controls received an i.v. challenge with 10 mg, 20 mg and 40 mg 5-HTP and placebo in random order on four different occasions. Before, during and until 2 h after 5-HTP administration anxious and depressive symptomatology was assessed. In addition, plasma levels of 5-HTP, cortisol, and 5-HIAA were measured at several timepoints. During and after infusion of placebo or any of the different dosages of 5-HTP, none of the patients or controls experienced a panic attack or showed an increase in anxiety or depressive symptoms. There was a dose-related increase in side effects, like nausea, dizziness and fatigue. Only infusion with 40 mg 5-HTP led to an increase in plasma cortisol in both patients and controls. The observed increase in plasma cortisol level was higher for patients compared to controls only at 30 min after infusion. In conclusion, stimulation of the serotonergic neuronal system by three different dosages of 5-HTP did not induce panic or anxiety in PD patients and healthy controls. The 5-HT hypersensitivity hypothesis of PD could not be confirmed in the present study.

Endocrine and cardiovascular responses to a series of graded physical and psychological stress stimuli in healthy volunteers

To investigate the endocrine and cardiovascular responses to a series of psychological and physical stress stimuli and to investigate the possibility of a stimulus intensity-response relation of endocrine and cardiovascular reactivity, 18 healthy volunteers were exposed to psychological and physical stimuli of increasing intensity. Each volunteer participated in three experimental sessions on separate days. The sequence of the sessions was such that all volunteers first participated in a session in which they were not exposed to a stress stimulus, i.e. the control session. Then they were randomly assigned to enter two trial sessions in which they were consecutively exposed to a series of psychological stressors and a series of physical stressors. During each session blood pressure (BP) and heart rate (HR) were assessed and blood samples were taken, to determine cortisol and noradrenaline levels. During the physical stress session increments in systolic and diastolic blood pressure and noradrenaline were observed, proportional to the intensity of the stimuli. In contrast, during the psychological stress session pronounced increments in heart rate were observed, with maximum responses at the second and third stimuli. Diastolic blood pressure responses showed a similar pattern, whereas no changes in noradrenaline were observed. Plasma cortisol was not increased by the psychological stressor, whereas it was stimulated by the physical stressor but at the highest stimulus intensity only. Although the size of the study population precludes any firm conclusions, the results suggest that a stimulus intensity approach in human stress research is possible. Furthermore, the results also appear to indicate that the cardiovascular and pituitary-adrenal systems may display stress-specific responses.

Differential effects of the D1-DA receptor antagonist SCH39166 on positive and negative symptoms of schizophrenia

In the present open study the effects of the D1-dopamine antagonist SCH 39166 on positive and negative symptoms of schizophrenia (DSM-IIIR) were investigated. SCH 39166 was given orally according to a fixed dosage schedule (day 1: 25 mg b.i.d; day 4: 50 mg b.i.d.; day 7: 100 mg b.i.d.; day 18: 200 mg b.i.d.; day 21: 225 mg b.i.d.). Seven patients completed 2 weeks, and five patients completed the study. The reason for premature withdrawal was lack of efficacy or refusal to take SCH 39166. In none of the patients a reduction of the BPRS or CGI score was found. As measured with the PANSS, a significant reduction was observed in the score of the negative subscale, whereas the positive symptoms scale and general psychopathology score remained unaffected. Akathisia, rigidity and hypokinesia were reported occasionally, although only mild in severity. The results of the present study do not support the hypothesis that D1-dopamine antagonists are clinically effective antipsychotics in schizophrenia, considering the fact that SCH 39166 had no effect on positive symptoms. The present study provides circumstantial evidence for an effect of SCH 39166 on negative symptoms.

Immunoglobulin production in vitro in major depression: a pilot study on the modulating action of endogenous cortisol

To investigate the possible differential sensitivity of hydrocortisone (HCO) on immunoglobulin (Ig) production in depression in relation to endogenous cortisol levels, blood was obtained at 8 AM and 4 PM from 10 inpatients with major depression according to DSM-III-R criteria and 10 age- and sex-matched healthy subjects. Peripheral blood lymphocytes were cultured in the presence of graded concentrations (10(-9)-10(-5) M) of HCO to study the effect on immunoglobulin (IgG and IgM) synthesis. In addition, peripheral blood lymphocytes were cultured in the presence of pokeweed mitogen (PWM) to study any additional effect of graded concentrations of HCO (10(-9)-10(-5) M) on IgG and IgM synthesis. Mean plasma cortisol levels at both time points were higher in patients compared to controls. HCO--preferentially at concentrations of 10(-8)-10(-6) molar--stimulated IgG and IgM production in controls, except for IgM production in the 8 AM samples, when the cells were cultured in the absence of PWM. Under these culture conditions, HCO stimulated IgG but not IgM synthesis in depressed patients. PWM-driven IgG and IgM synthesis in controls was stimulated by HCO in both the 8 AM and the 4 PM samples. In patients PWM driven IgG synthesis was stimulated by HCO in the 8 AM but not in the 4 PM samples. PWM-stimulated IgM synthesis was not augmented by HCO in depressed patients. We conclude that a differential sensitivity to the effects of HCO exists in in vitro IgG and IgM synthesis between depressed patients and controls. Furthermore, we suggest that immunocompetent cells of depressed patients possess corticosteroid-resistant properties.

Noradrenaline concentrations and electrocardiographic abnormalities after aneurysmal subarachnoid haemorrhage

Serial ECGs and serial assessment of plasma noradrenaline concentrations were carried out in 37 consecutive patients with aneurysmal subarachnoid haemorrhage and 18 operated controls. Electrocardiographic abnormalities reflecting possible signs of cardiac ischaemia occurred significantly more often in patients than in controls. By contrast, plasma noradrenaline concentrations were much higher in controls than in patients. Plasma noradrenaline concentrations were higher in patients with poor outcome, particularly after the third day, but showed covariance with established predictors of outcome such as the Glasgow coma scale score on admission, the amount of extravasated blood on the initial CT, and age. In conclusion, high plasma noradrenaline concentrations do not explain the occurrence of electrocardiographic abnormalities, and are not useful as independent predictors of poor outcome or secondary complications.

Effects of single and repeated oral administration of fluvoxamine on extracellular serotonin in the median raphe nucleus and dorsal hippocampus of the rat

The delay in clinical effects of selective serotonin reuptake inhibitors (SSRIs) suggest the existence of adaptive phenomena, such as receptor sensitivity changes. To examine the effects of repeated administration of SSRIs on serotonin neurotransmission, we investigated the effects of acute and chronic administration of the SSRI fluvoxamine on the extracellular levels of 5-HT in the median raphe nucleus and dorsal hippocampus of conscious rats by means of brain microdialysis. A single oral dose of fluvoxamine (30 mg/kg) augmented extracellular 5-HT in the median raphe and dorsal hippocampus to 270 and 191% of baseline level, respectively. Administration of fluvoxamine (30 mg/kg) or vehicle for 14 days did not affect 5-HT baseline levels. Moreover, the increase in extracellular 5-HT in the median raphe nucleus and dorsal hippocampus after an oral dose of fluvoxamine (30 mg/kg) in rats chronically treated with fluvoxamine was not different from rats treated with vehicle. Using RU 24969 as a probe for the sensitivity of the 5-HT1B autoreceptors in the dorsal hippocampus, no change in receptor sensitivity could be observed. These results demonstrate that repeated oral treatment with fluvoxamine does not affect extracellular 5-HT in the median raphe and dorsal hippocampus, suggesting that presynaptic functional changes of 5-HT in the brain areas tested are not implicated in the observed delayed onset of action of this SSRI in humans.

Chronic treatment with fluvoxamine by osmotic minipumps fails to induce persistent functional changes in central 5-HT1A and 5-HT1B receptors, as measured by in vivo microdialysis in dorsal hippocampus of conscious rats

This study investigated the alterations of the 5-HT1A and 5-HT1B autoreceptor function following chronic treatment with fluvoxamine using osmotic minipumps. The 5-HT1A and 5-HT1B autoreceptor function were studied using microdialysis in the dorsal hippocampus. The effect of the 5-HT1A receptor agonist 8-OH-DPAT (0.3 mg/kg, SC) and the 5-HT1B receptor agonist RU-24969 (100 nM through the dialysis probe for 30 min) on 5-HT release was compared with rats chronically treated with saline. 8-OH-DPAT decreased 5-HT release to 55% and 60% of baseline, while RU-24969 decreased 5-HT release to 66% and 70% of baseline value in the saline and fluvoxamine group, respectively. In both cases, differences between the saline and fluvoxamine groups were not statistically significant. Plasma levels of fluvoxamine after 21 days of treatment ranged from 3 to 5 ng/ml. Fluvoxamine concentration in rat brain during treatment was estimated between 100 and 200 nM, which approximates to the IC50 value of fluvoxamine on the 5-HT transporter in synaptosomes and is 50 times higher than the Kd value for the 5-HT reuptake site. In conclusion, no evidence was found for changes in 5-HT1A,B receptor function using 8-OH-DPAT and RU-24969 as probes after continuous treatment with fluvoxamine by means of osmotic minipumps.

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.

Biological dissection of anxiety disorders: the clinical role of selective serotonin reuptake inhibitors with particular reference to fluvoxamine

The selective serotonin reuptake inhibitor (SSRI) fluvoxamine has been used in an attempt to understand whether there is a biological distinction among anxiety disorders. A comparison of fluvoxamine with the specific noradrenaline reuptake inhibitor maprotiline in patients with panic disorder showed fluvoxamine to be a potent anti-panic agent, whereas maprotiline had no effect on the frequency of panic attacks. This result supported the hypothesis of serotonergic involvement in the pathogenesis of panic disorder. In a second study, unlike fluvoxamine, the 5-HT2A/2C antagonist ritanserin had no effect on the number of panic attacks, or phobic avoidance. This suggested that the efficacy of antidepressants in panic disorder was not a result of down-regulation of postsynaptic 5-HT2 receptors. Most studies suggest that the efficacy of antidepressants in obsessive-compulsive disorder (OCD) is not related to their antidepressant or mood-enhancing effects. Fluvoxamine has also been shown to reduce general and phobic anxiety in social phobia patients. In conclusion, serotonergic systems are implicated in the pathophysiology of global anxiety irrespective of the nosological background, and SSRIs, exemplified by fluvoxamine, appear to be effective in panic disorder, OCD and probably also social phobia.

Recent developments in the psychopharmacology of social phobia

The past 2 decades have witnessed an upsurge in the interest in anxiety disorders. Much research effort has been dedicated to panic disorder and obsessive-compulsive disorder. However, it is only very recently that we have begun to understand some of the basic principles about the psychopharmacology of social phobia. Drug classes thus far studied include beta-blockers, nonselective and irreversible monoamine oxidase inhibitors (MAOIs), and benzodiazepines. Beta blockers appear to be of use in specific social phobias, such as public speaking, whereas they are of little use in generalized social phobia. There is considerable evidence suggesting that MAOIs are effective in reducing both social anxiety as well as social avoidance in generalized social phobia. A disadvantage of the conventional irreversible MAOIs is their risk for hypertensive crises when combined with dietary tyramine. Thus far only a small number of studies with selective MAO-A inhibitors, such as moclobemide and brofaromine, have been conducted in social phobia, and the results indicate that both compounds are effective. Drugs exerting selective and specific actions on certain components of, for example, the serotonergic system, can now be studied, and it is hoped that the role of 5-hydroxytryptamine) and other neuronal systems in social phobia can be elucidated. In order to gain more information about selective serotonergic drugs, the first double-blind placebo-controlled study with fluvoxamine was recently published. Preliminary results indicate a reduction in social anxiety after a prolonged treatment period. Finally, the role of peptides in the treatment of social phobia is critically reviewed. The MSH/ACTH analog Org 2766 was investigated in patients suffering from social phobia.(ABSTRACT TRUNCATED AT 250 WORDS)

On the significance of cholecystokinin receptors in panic disorder

Interest in the biological aspects of panic disorder has been focussed mainly on the noradrenergic and serotonergic systems in the brain. Recently evidence has been found that Cholecystokinin (CCK) receptors in the Central Nervous System (CNS) may be involved in panic disorders. This hypothesis is based on the results of animal electrophysiological studies, animal models of anxiety and on challenge test using CCK fragments in humans. In this review, the studies evaluating the putative involvement of CCK, and especially CCK-B receptors, in panic disorder will be discussed.

5-Hydroxytryptamine release in dorsal hippocampus of freely moving rats: modulation by pindolol

1. The aim of the present study was to investigate the origin and modulation of 5-hydroxytryptamine release in dorsal hippocampus of freely moving rats using brain microdialysis. 2. Basal release of 5-hydroxytryptamine and 5-hydroxyindole-acetic acid was 3.0 +/- 0.2 pg/15 min and 519 +/- 18 pg/15 min, respectively. Stimulation by 60 mM K+ increased 5-hydroxytryptamine release by 66%. Inclusion of 10 microM tetrodotoxin in the perfusion medium reduced 5-hydroxytryptamine release to approximately 5% of basal levels. 3. In addition, release could be modulated by the 5-hydroxytryptamine receptor agonist 8-hydroxy-2-(di-N-propylamino)-tetralin (50 % decrease) and this effect was completely blocked by the 5-hydroxytryptamine-1 receptor antagonist pindolol. 4. These data are in concordance with results from the ventral hippocampus and indicate that release of 5-hydroxytryptamine is predominantly of neuronal origin. In contrast with other studies, the authors found the non-selective 5-hydroxytryptamine-1 antagonist, pindolol, to increase 5-hydroxytryptamine release by 65% following systemic administration. This may hint at a different autoreceptor control in serotonergic fibers ascending from the median raphe as compared to the dorsal raphe nucleus.

Recent advances in the psychopharmacology of social phobia

1. The last two decades have witnessed an upsurge in the interest in anxiety disorders. Much research effort has been dedicated to panic disorder and obsessive compulsive disorder. However, it is only very recently that we have begun to understand some of the basic principles about the psychopharmacology of social phobia. 2. Drug classes sofar studied include beta-blockers, nonselective and irreversible MAO-inhibitors (MAOI's) and benzodiazepines. 3. Beta blockers appear to be of use in specific social phobias, like public speaking. There is considerable evidence suggesting that MAOI's are effective in reducing both social anxiety as well as social avoidance. A disadvantage of the conventional irreversible MAOI's is their risk for hypertensive crises when combined with dietary tyramine. So far only a small number of studies with selective MAOI-A inhibitors such as moclobemide and brofaromine have been conducted in social phobia, and the results indicate that both compounds are effective. 4. Drugs exerting selective and specific actions on certain compounds of e.g. the serotonergic system can now be studied and it is hoped that the role of 5-HT and other neuronal systems in social phobia can be elucidated. 5. In order to gain more information about selective serotonergic drugs the first double blind placebo controlled study with fluvoxamine in social phobia is here reported. Preliminary results indicate a reduction of social anxiety. 6. Finally the role of peptides in the treatment of social phobia is critically reviewed. The MSH/ACTH analog Org 2766 was investigated in patients suffering from social phobia. No anxiolytic effects of this peptide could be observed.

Psychopharmacological treatment of social phobia; a double blind placebo controlled study with fluvoxamine

Previous studies have shown selective and nonselective monoamine oxidase inhibitors (MAOIs) to be effective in the treatment of social phobia. In this study we investigated the efficacy of selective serotonin reuptake inhibitors (SSRIs) in social phobia. Thirty patients with social phobia (DSM-IIIR) were treated with the SS-RI fluvoxamine (150 mg daily) using a 12-week double-blind placebo controlled design. A substantial improvement was observed in seven (46%) patients on fluvoxamine and in one (7%) on placebo. Statistically significant effects were seen on measures of social anxiety and general (or anticipatory) anxiety in patients treated with fluvoxamine compared with placebo. The level of phobic avoidance decreased also but the difference at endpoint between fluvoxamine and placebo failed to reach statistical significance. It is concluded that treatment with the SSRI fluvoxamine has beneficial effects in patients suffering from social phobia, suggesting that serotonergic mechanisms might be implicated in social anxiety.

Pentagastrin induced panic attacks: enhanced sensitivity in panic disorder patients

The effects of pentagastrin, a synthetic analogue of the cholecystokinin tetrapeptide (CCK4), were studied in 15 patients with panic disorder and 15 healthy controls. Three different intravenous dosages of pentagastrin (0.1, 0.3 and 0.6 microgram/kg) and saline were investigated. Subjects were randomly allocated to two of the four treatment groups and tested on two separate occasions, 1 week apart, using an unbalanced double-blind incomplete block design. The mean panic rate with pentagastrin was 55% (12/22) for patients and 5% (1/22) for controls. None of the subjects panicked with saline. The frequency of panic attacks between the three pentagastrin doses in patients was not different. One control subject had a panic-like attack at the highest dose of pentagastrin. These findings concur with previous studies on the panicogenic effect of CCK4 and pentagastrin and suggest a greater sensitivity for CCK receptor agonists in patients suffering from panic disorder than in healthy controls.

Pharmacokinetics of DGAVP in plasma following intranasal and oral administration to healthy subjects

A pharmacokinetic study was carried out to assess the bioavailability of desglycinamide-[Arg8]vasopressin (DGAVP, Org 5667). DGAVP (2 mg) was administered both intranasally and orally to healthy subjects with a treatment interval of 1 week. Blood samples were taken regularly between 15 min before and 210 min after administration and were assayed for DGAVP by radioimmunoassay. In all subjects endogenous vasopressin (AVP) levels were detectable. Peak levels of DGAVP occurred at 15 min after both treatments. The mean absorption half-life was 8.7 and 7.3 min and the mean elimination half-life was 38 and 34.6 min for the intranasal and oral route of administration, respectively. The bioavailability of orally administered DGAVP was low compared with the intranasally administered drug; the relative bioavailability of oral/nasal administration was 0.7%. The results indicate that DGAVP is absorbed rapidly after both oral and intranasal administration, but the intranasal route of administration of DGAVP is 100 times more effective in increasing plasma DGAVP levels.

Stimulation of the pituitary-adrenal system with graded doses of CRH and low dose vasopressin infusion in depressed patients and healthy subjects: a pilot study

A corticotropin-releasing hormone (CRH) stimulation test with four cumulative doses of human CRH (0.01, 0.06, 0.2 and 1 microgram/kg body weight) and infusion of a low dose of [Arg8]-vasopressin (0.004 U/kg body weight/30 min) was performed in five depressed patients and six healthy subjects. Plasma samples for the measurement of cortisol, ACTH and beta-endorphin were taken at regular intervals and considered as measures of pituitary-adrenal function. A dose-response relationship between CRH and the hormones measured was found in patients and controls. Depressed patients already responded to the lowest dose of CRH with respect to cortisol release, whereas ACTH and beta-endorphin responded to the second and third doses, respectively. In control subjects the cortisol and ACTH response started after the third dose of CRH, whereas beta-endorphin responded significantly to the highest dose only. When both groups were compared, differences in response were found to the higher doses of CRH with respect to cortisol, ACTH and, less markedly, beta-endorphin and to the lowest dose of CRH with respect to cortisol. Although numbers are small, the data show 'blunting' of the ACTH response to the higher doses of CRH in patients with an enhanced cortisol response of the adrenals to lower and higher doses of CRH. There was no significant difference in response when CRH was used with vasopressin as compared to treatment with CRH alone. Thus, in this design vasopressin did not contribute significantly to CRH activity. The data suggest that pituitary cell sensitivity might be changed in depression as part of HPA dysfunction.