Serum C-reactive protein level and sleep characteristics in obstructive sleep apnea syndrome comorbid with panic disorder: a preliminary study

OBJECTIVE

Investigate the sleep characteristics of patients with obstructive sleep apnea syndrome (OSAS) comorbidity with panic disorder (PD), exploring its potential association with serum C-reactive protein (CRP) levels.

PATIENTS AND METHODS

Fifty-four patients (25 OSAS patients with PD and 29 without PD) and 25 healthy controls (HCs) were included. The Self-rating anxiety scale (SAS), self-rating depression scale (SDS), and Pittsburgh sleep quality index (PSQI) were used to assess the mood and sleep quality of the subjects. All patients had circulating CRP levels and polysomnography was performed.

RESULTS

OSAS with PD had higher SAS, SDS, PSQI than the OSAS without PD. Compared to OSAS without PD, OSAS with PD had higher percentage of non- rapid eye movement sleep 1 and 2 (N1 and N2%), sleep latency, and a lower percentage of rapid eye movement sleep (REM%). Respiratory-related microarousal index, AHI, and time below 90% oxygen saturation (T90) were low, and the lowest oxygen saturation (LO2) was high. Serum CRP levels in OSAS patients with PD were lower than that in OSAS patients without PD, but higher than that in HCs. In OSAS patients with PD, serum CRP levels were negatively correlated with wake time after sleep onset and SAS scores but positively correlated with sleep efficiency and N2%. Serum CRP levels were positively correlated with T90 and negatively correlated with LO2.

CONCLUSION

OSAS patients with PD had worse sleep quality, less severe OSAS, and low serum CRP levels. Serum CRP levels in OSAS patients with PD were associated with poorer sleep quality and duration of hypoxia rather than AHI.

Understanding importance of clinical biomarkers for diagnosis of anxiety disorders using machine learning models

Anxiety disorders are a group of mental illnesses that cause constant and overwhelming feelings of anxiety and fear. Excessive anxiety can make an individual avoid work, school, family get-togethers, and other social situations that in turn might amplify these symptoms. According to the World Health Organization (WHO), one in thirteen persons globally suffers from anxiety. It is high time to understand the roles of various clinical biomarker measures that can diagnose the types of anxiety disorders. In this study, we apply machine learning (ML) techniques to understand the importance of a set of biomarkers with four types of anxiety disorders—Generalized Anxiety Disorder (GAD), Agoraphobia (AP), Social Anxiety Disorder (SAD) and Panic Disorder (PD). We used several machine learning models and extracted the variable importance contributing to a type of anxiety disorder. The study uses a sample of 11,081 Dutch citizens’ data collected by the Lifelines, Netherlands. The results show that there are significant and low correlations among GAD, AP, PD and SAD and we extracted the variable importance hierarchy of biomarkers with respect to each type of anxiety disorder which will be helpful in designing the experimental setup for clinical trials related to influence of biomarkers on type of anxiety disorder.

Ratio of plasma BDNF to leptin levels are associated with treatment response in major depressive disorder but not in panic disorder: A 12-week follow-up study

BACKGROUND

A link between brain-derived neurotrophic factor (BDNF) expression and the mood regulatory effect of leptin has been suggested in the pathophysiology of major depressive disorder (MDD). We investigated treatment response and pre-treatment leptin and BDNF in patients with MDD and with panic disorder (PD).

METHODS

We recruited 41 patients with MDD, 52 patients with PD, and 59 matched healthy controls. All subjects completed five visits (at baseline, 2, 4, 8, and 12 weeks), and both MDD and PD patients were treated with standard pharmacotherapy for 12 weeks. Plasma BDNF (pBDNF) and blood leptin levels were obtained along with a 17-item Hamilton Depression Scale rating (HDRS-17) score at every visit.

RESULTS

The ratio of pre-treatment pBDNF to leptin was significantly lower in patients with MDD and PD compared to healthy controls (p = 0.024), but was not associated with severity of depressive or anxiety symptoms. Pre-treatment pBDNF:leptin ratio was significantly higher in treatment responders than in non-responders (p = 0.012) in MDD but not in PD. This difference was larger in MDD patients with appetite loss (p = 0.034). In multivariate analysis, pre-treatment pBDNF:leptin ratio was significantly associated with treatment responsiveness (Adjusted Odds Ration [AOR] = 2.50, 95% CI 1.02-6.14) in MDD.

LIMITATION

small sample size; limited information on detailed pharmacological effects.

CONCLUSIONS

A relatively higher ratio of pre-treatment pBDNF to leptin was associated with greater treatment response in MDD but not in PD. Further research should focus on exploration of a link between BDNF and leptin underlying neuronal plasticity in depression.

Paraoxonase1 192 (PON1 192) gene polymorphism and serum paraoxonase activity in panic disorder patients

BACKGROUND/AIM

Reactive oxygen species (ROS) are involved in the development of certain neuropsychiatric disorders. Paraoxonase 1 (PON1) activity has been suggested to be adversely related to oxidative stress in plasma. The purpose of the present study was to demonstrate the relationship between serum PON1 activity and PON1 192 polymorphism in panic disorder (PD).

MATERIALS AND METHODS

Fourty-two patients with PD and 46 healthy controls were included in this study. PON1 192 genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. PON1 activity was measured by spectrophotometric assay of p-nitrophenol production following the addition of paraoxon.

RESULTS

PON1 192 AA genotype and A allele in PD were significantly higher than in the control group, whereas the B allele was found to be significantly higher in the control group. Patients with panic disorder have lower PON1 activity than the control group.

CONCLUSION

The PON1 192 AA genotype may increase the risk of PD depending on lipid peroxidation.

Alexithymia, suicide risk and serum lipid levels among adult outpatients with panic disorder

To elucidate the relationships between alexithymia, suicide ideation and serum lipid levels in drug-naïve adult outpatients with a DSM-IV diagnosis of Panic Disorder (PD), 72 patients were evaluated. Measures were the Panic Attack and Anticipatory Anxiety Scale, the Toronto Alexithymia Scale (TAS-20), the Scale of Suicide Ideation (SSI) and the Montgomery Åsberg Depression Rating Scale (MADRS). Alexithymic patients showed higher scores on all rating scales and altered serum lipid levels than non-alexithymics. In the hierarchical regression model, the presence of lower HDL-C and higher VLDL-C levels and Difficulty in Identifying Feelings dimension of TAS-20 were associated with higher suicide ideation. In conclusion, alexithymic individuals with PD may show a cholesterol dysregulation that may be linked to suicide ideation. The authors discuss study limitations and future research needs.

Immunoglobulin levels in panic disorder patients

The study was conducted to evaluate the serum immunoglobulin levels in patients suffering from panic disorder and to assess the relationship between the changes of immunoglobulin levels and the socioeconomic parameters, as well as nutritional status. 54 panic patients were randomly selected from the Department of Psychiatry, Bangabandhu Sheikh Mujib Medical University (BSMMU) and Dhaka Medical College Hospital, Bangladesh. Fifty two, age and gender matched healthy volunteers (42 males and 10 females, mean age of 30 ± 6 yrs) were also enrolled in this study. Immunoglobulin levels were measured by turbidimetry method using immunoglobulin kits. It was found that the mean serum immunoglobulin concentrations of IgG, IgM and IgA of panic disorder patients were 0.999±0.26 (g/L), 0.1±0.028 (g/L) and 0.194±0.066 (g/L) respectively whereas the values were 1.24± 0.39 ( g/L ), 0.096±0.022 ( g/L) , 0.194±0.053 (g/L) in healthy volunteers. IgG level in panic disorder patient was found significantly (p <0.05) lower than that of the controls but the change in concentration of IgM and IgA were not significant (p=0.497, p=0.962). Socioeconomic data reveals that most of the patients were from lower income group and educated. BMI (Mean±SD) of the patients (22.62 ± 3.74 kg/m2) and controls (23.74 ± 2.71 kg/m2) were well within the normal range. From correlative analysis it has been found that income has significant effect (p=0 .047) on the change of the serum IgG level in panic disorder patient and it was also been justified by the regression analysis (p=0.049). This finding may play a key role in the diagnosis and treatment of the panic disorder patients. Further studies have been suggested with a large number of populations to confirm these findings.

Respiratory and cognitive mediators of treatment change in panic disorder: evidence for intervention specificity

OBJECTIVE

There are numerous theories of panic disorder, each proposing a unique pathway of change leading to treatment success. However, little is known about whether improvements in proposed mediators are indeed associated with treatment outcomes and whether these mediators are specific to particular treatment modalities. Our purpose in this study was to analyze pathways of change in theoretically distinct interventions using longitudinal, moderated mediation analyses.

METHOD

Forty-one patients with panic disorder and agoraphobia were randomly assigned to receive 4 weeks of training aimed at altering either respiration (capnometry-assisted respiratory training) or panic-related cognitions (cognitive training). Changes in respiration (PCO₂, respiration rate), symptom appraisal, and a modality-nonspecific mediator (perceived control) were considered as possible mediators.

RESULTS

The reductions in panic symptom severity and panic-related cognitions and the improvements in perceived control were significant and comparable in both treatment groups. Capnometry-assisted respiratory training, but not cognitive training, led to corrections from initially hypocapnic to normocapnic levels. Moderated mediation and temporal analyses suggested that in capnometry-assisted respiratory training, PCO₂ unidirectionally mediated and preceded changes in symptom appraisal and perceived control and was unidirectionally associated with changes in panic symptom severity. In cognitive training, reductions in symptom appraisal were bidirectionally associated with perceived control and panic symptom severity. In addition, perceived control was bidirectionally related to panic symptom severity in both treatment conditions.

CONCLUSION

The findings suggest that reductions in panic symptom severity can be achieved through different pathways, consistent with the underlying models.

Serum hepatocyte growth factor levels and the effects of antidepressants in panic disorder

Previous animal studies have suggested that hepatocyte growth factor (HGF) could be associated with depression- and anxiety-related behaviors. Our aim was to relate serum HGF levels with State-Trait Anxiety Inventory (STAI), Profile of Mood State (POMS), and Revised NEO Personality Inventory (NEO-PI-R) scores in patients with panic disorder (with or without agoraphobia) and healthy controls. We examined 67 patients with panic disorders and 97 controls. Patients were split into two groups according to whether they exhibited a 50% improvement in test scores (good/high response group: n = 26) or not (poor/low response group: n = 41). In both healthy control and panic disorder individuals, there were no significant associations between HGF serum levels and STAI or NEO-PI-R scores. However, there was a significant correlation between serum HGF levels and fatigue in healthy control subjects in as scored by POMS testing. HGF concentration in the good/high response group was significantly elevated compared to both the low/poor response group (p < 0.01) and the control group (p < 0.01). HGF levels in the poor response group did not differ from the control group (p = 0.48). These results indicate that increased serum HGF levels might be a requirement for antidepressant efficacy in patients with panic disorders.

Comparative analysis of serum manganese, zinc, calcium, copper and magnesium level in panic disorder patients

The purpose of the study was to determine the serum concentration of trace elements of panic disorder patients and to find out the relationship between trace element levels and nutritional status or socio-economic factors. The study was conducted among 54 panic disorder patients and 52 healthy volunteers. Patients were recruited from Bangabandhu Sheikh Mujib Medical University by random sampling. Serum trace element concentrations were determined by flame atomic absorption spectroscopy (for Mg, Zn, Ca, and Cu) as well as graphite furnace (for Mn). Data were analyzed by independent t test, Pearson's correlation analysis, regression analysis, and ANOVA. The serum concentration of Mn, Zn, Ca, Cu, and Mg in panic disorder patients were 0.37 +/- 0.30, 0.67 +/- 0.20, 99.91 +/- 15.15, 0.83 +/- 0.23, and 21.14 +/- 3.72 mg/L, while those were 0.4163 +/- 0.2527, 0.86 +/- 0.3, 106.6073 +/- 18.6531, 0.8514 +/- 0.3646, and 21.37 +/- 2.03 mg/L in control subjects, respectively. The serum concentration of Zn decreased significantly (p = 0.001) in patient group. But the differences of the concentration of Mn, Ca, Cu, and Mg between patient and control group were not significant (p = 0.522, p = 0.065, p = 0.800, and p = 0.712, respectively). Socio-economic data reveal that most of the patients were very poor and middle aged. Mean BMIs of the control group (23.74 +/- 2.71 kg/m(2)) and the patient group (22.62 +/- 3.74 kg/m(2)) were within the normal range (18.5-25.0 kg/m(2)). There was no significant relationship between serum zinc level and BMI of patients (r = 0.038; p = 0.809). So the decreased level of serum zinc in panic disorder patients was not because of other reasons, but rather it may provide a prognostic tool for the diagnosis and treatment of this disease.

Blood lead levels and major depressive disorder, panic disorder, and generalized anxiety disorder in US young adults

CONTEXT

Lead is a ubiquitous neurotoxicant, and adverse cognitive and behavioral effects are well-documented in children and occupationally exposed adults but not in adults with low environmental exposure.

OBJECTIVE

To investigate the association of current blood lead levels with 3 common psychiatric disorders-major depression, panic, and generalized anxiety-in young adults.

DESIGN

Cross-sectional epidemiologic survey.

SETTING

Nationally representative sample of US adults.

PARTICIPANTS

A total of 1987 adults aged 20 to 39 years who responded to the National Health and Nutrition Examination Survey (1999-2004).

MAIN OUTCOME MEASURES

Twelve-month DSM-IV criteria-based diagnoses of major depressive disorder, panic disorder, and generalized anxiety disorder assessed using the Composite International Diagnostic Interview.

RESULTS

The mean (SD) blood lead level was 1.61 (1.72) microg/dL (range, 0.3-37.3 microg/dL) (to convert to micromoles per liter, multiply by 0.0483). Increasing blood lead levels were associated with higher odds of major depression (P = .05 for trend) and panic disorder (P = .02 for trend) but not generalized anxiety disorder (P = .78 for trend) after adjustment for sex, age, race/ethnicity, education status, and poverty to income ratio. Persons with blood lead levels in the highest quintile had 2.3 times the odds of major depressive disorder (95% confidence interval [CI], 1.13-4.75) and 4.9 times the odds of panic disorder (1.32-18.48) as those in the lowest quintile. Cigarette smoking was associated with higher blood lead levels and outcome, but models that excluded current smokers also resulted in significantly increased odds of major depression (P = .03 for trend) and panic disorder (P = .01 for trend) with higher blood lead quintiles.

CONCLUSIONS

In these young adults with low levels of lead exposure, higher blood lead levels were associated with increased odds of major depression and panic disorders. Exposure to lead at levels generally considered safe could result in adverse mental health outcomes.

Acute exercise reduces the effects of a 35% CO2 challenge in patients with panic disorder

BACKGROUND

Chronic exercise has been shown to have therapeutic effects in panic disorder (PD). The mechanism of these effects is unknown. Acute exercise reduces the effect of a panic challenge in healthy volunteers. Such an effect has not yet been demonstrated in PD patients. The present study aimed at exploring the antipanic effects of acute exercise on a 35% CO2 panic provocation in treatment-naïve PD patients to further elucidate the mechanisms of the beneficial effects of exercise on panic.

METHODS

Eighteen PD patients performed either moderate/hard exercise or very-light exercise before a 35% CO2 challenge in a randomized, between-group design. The reactivity to CO2 was assessed with the Visual Analogue Anxiety Scale and the DSM-IV Panic Symptom List.

RESULTS

Panic reactions to CO2 were smaller in patients that performed moderate/hard exercise in contrast to those that performed very-light exercise. Increments in both measurements and panic rates were consistently reduced by intense exercise.

LIMITATIONS

Since this study focuses on the acute effects of exercise on CO2 sensitivity in patients with PD, the results of repetitive exercise sessions on the rate of spontaneous panic attacks and overall symptoms are warranted. The small sample size and other limitations are addressed.

CONCLUSIONS

Exercise reduced the panicogenic effects of a CO2 challenge. In addition to its therapeutic potential, exercise may also be useful as a laboratory maneuver with heuristic value in experimental research into the mechanisms of antipanic treatment.

[Serum-blood serotonin level as a marker of panic attacks severity and effectiveness of their treatment]

Twenty-eight males with psychogenic (emotiogenic) autonomic dystonia with paroxysmal course (panic attacks) have been studied. Serum serotonin (S) concentration has been measured using ELISA. The deficit (147,36+/-69,80 ng/ml) of humoral S has been found compared to a control group (295,18+/-152,38 ng/ml). After the 8-weeks treatment with a SSRIs antidepressant rexetin in dosage 20 mg/day, a distinct clinical effect has been observed. There was a decrease of the number and severity of paroxysms as well as severity of symptoms of psychoautonomic syndrome (the reduction of depression, anxiety and optimization of autonomic regulation). Despite the therapeutic effectiveness of rexetin, serum S concentration has decreased still more to 59,92+/-23,06 ng/ml. The paradoxical phenomenon of growing deficit in the humoral pattern of serotonergic system during the short-term course of SSRIs antidepressant treatment is reviewed as a result of the transfer of neuromediator from the blood to the cerebral structures with the following activation of serotonergic system that provides the therapeutic effect.

[Levels of adenosine deaminase and dipeptidyl peptidase IV in patients with panic disorder]

OBJECTIVE

Adenosine deaminase and dipeptidyl peptidase IV are enzymes connected to T cells that play an important role in immune system functioning. In this study, in order to understand the immune processes in panic disorder, we determined the serum levels of adenosine deaminase and dipeptidyl peptidase IV in medication-free panic disorder patients and compared them to those of healthy controls.

METHOD

Enzymes levels were determined in blood samples of 24 healthy controls and 33 panic disorder patients diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders-IV that were medication free during the previous month and medically healthy.

RESULTS

Levels of both enzymes were significantly higher in panic disorder patients than in the controls (P<0.001 for adenosine deaminase and P<0.05 for dipeptidyl peptidase IV). The levels of the enzymes did not correlate with sociodemographic variables, duration of the disorder, presence of agoraphobia, presence of stressors, number of panic attack symptoms, and Hamilton depression and anxiety rating scale scores. In addition, the 2 enzymes? levels did not correlate with each other. There was a correlation between Hamilton anxiety rating scale score and the number of panic attack symptoms (P<0.001); however, Hamilton anxiety rating scale scores were not correlated with the other variables.

CONCLUSION

Our results suggest that there may be a primary or secondary impaired immune state in the course of panic disorder, as there is in many other psychiatric disorders, such as major depression. Future studies with larger samples are needed to clarify the relationship between the immune system and panic disorder.

Increased brain serotonin turnover in panic disorder patients in the absence of a panic attack: reduction by a selective serotonin reuptake inhibitor

Since the brain neurotransmitter changes characterising panic disorder remain uncertain, we quantified brain noradrenaline and serotonin turnover in patients with panic disorder, in the absence of a panic attack. Thirty-four untreated patients with panic disorder and 24 matched healthy volunteers were studied. A novel method utilising internal jugular venous sampling, with thermodilution measurement of jugular blood flow, was used to directly quantify brain monoamine turnover, by measuring the overflow of noradrenaline and serotonin metabolites from the brain. Radiographic depiction of brain venous sinuses allowed differential venous sampling from cortical and subcortical regions. The relation of brain serotonin turnover to serotonin transporter genotype and panic disorder severity were evaluated, and the influence of an SSRI drug, citalopram, on serotonin turnover investigated. Brain noradrenaline turnover in panic disorder patients was similar to that in healthy subjects. In contrast, brain serotonin turnover, estimated from jugular venous overflow of the metabolite, 5-hydroxyindole acetic acid, was increased approximately 4-fold in subcortical brain regions and in the cerebral cortex (P < 0.01). Serotonin turnover was highest in patients with the most severe disease, was unrelated to serotonin transporter genotype, and was reduced by citalopram (P < 0.01). Normal brain noradrenaline turnover in panic disorder patients argues against primary importance of the locus coeruleus in this condition. The marked increase in serotonin turnover, in the absence of a panic attack, possibly represents an important underlying neurotransmitter substrate for the disorder, although this point remains uncertain. Support for this interpretation comes from the direct relationship which existed between serotonin turnover and illness severity, and the finding that SSRI administration reduced serotonin turnover. Serotonin transporter genotyping suggested that increased whole brain serotonin turnover most likely derived not from impaired serotonin reuptake, but from increased firing in serotonergic midbrain raphe neurons projecting to both subcortical brain regions and the cerebral cortex.

Delayed increase in LDL cholesterol following pentagastrin-induced panic attacks

OBJECTIVE

Panic disorder (PD) has been associated with an increased risk for cardiovascular (CV) morbidity and mortality. There are inconsistent reports of increased low-density lipoprotein cholesterol (LDL-C) in patients with PD. Studies have reported a correlation between cholesterol levels and the intensity and frequency of panic attacks (PAs), suggesting that an elevation in cholesterol could be due to physiological and neurochemical changes that occur during and after a PA. The objective of our study was to show that the occurrence of a PA is associated with an increase in LDL-C.

MATERIALS AND METHODS

We used a double-blind, placebo-controlled crossover design with randomized injections of placebo and pentagastrin in 18 patients with PD (11 men, 7 women) and 33 healthy-control subjects (24 men, 9 women).

RESULTS

Pentagastrin-induced PAs were associated with a statistically significant 10.4% delayed (24 h) increase in LDL-C levels in male subjects. Such an effect was not observed in female subjects.

CONCLUSION

LDL-C levels are directly affected by the occurrence of a PA in males. These findings, in association with previous reports of increased cholesterol levels in PD patients, suggest that a chronic increase in LDL-C as a result of frequent PAs may be one of the mechanisms that contributes, at least in male patients, to previously reported increased CV risk in patients with PD. The gender difference and the temporal association between PAs and increased LDL-C may explain the inconsistency in the findings of previous investigations of cholesterol levels in PD patients.

Blood B-type natriuretic peptide level increases in patients who complain shortness of breath and chest pain in the course of panic attack

OBJECTIVE

Blood pro-B-type natriuretic peptide (pro-BNP) level increases in case of myocardial ischemia and myocardial volume or pressure overload. The aim of this study is to measure changes in blood pro-BNP level during the course of panic attack with symptoms of chest pain and/or dyspnea.

METHODS

Patients who were admitted to the emergency room with panic attack have been regarded as the study group. Blood pro-BNP level has been measured during follow-up of the patients upon admission and 2h later.

RESULTS

Systolic and diastolic blood pressure and pulse rate were significantly decreased (p<0.0001) during follow-up of the patients (ages between 18 and 43 years; mean 26+/-6.13 years). Paradoxically, blood pro-BNP level of patients was significantly increased during the same period (52.86+/-59.73 versus 50.97+/-57.42 U/L; p<0.0001).

CONCLUSION

Blood pro-BNP level has increased among patients who have complained chest pain and/or dyspnea as symptoms of panic attack. It is thought that chest pain and dyspnea in the course of panic attack may not be purely psychological.

The speed of onset of action of alprazolam-XR compared to alprazolam-CT in panic disorder

This study compares the speed of onset of action of the extended release (XR) formulation of alprazolam with that of the compressed tablet (CT) formulation in a sample of outpatients with DSM-IV panic disorder. Diary records of hourly antianxiety benefit from a 9-week open label switch study of 30-patients stabilized on alprazolam- CT for 3 weeks and then switched to an equivalent dose of alprazolam-XR, were used to examine the timing and magnitude of clinical benefit on both formulations. The magnitude of benefit at the first hour after the first morning dose was similar for both formulations. The peak benefit, over the hours after the first morning dose, was also similar and 90% of peak benefit that was achieved in the first hour on both formulations. Mean time to peak benefit was similar (1.5 h for alprazolam-CT vs. 1.6 h for alprazolam-XR) and the percent of patients achieving peak benefit in the first hour was also similar. Compared to the CT formulation, alprazolam-XR had a much longer duration of therapeutic action (11.3 +/- 4.2 h vs. 5.1 +/- 1.7 h). The results, which may be related to the biotechnology (and resultant pharmacokinetic profile) of the XR preparation, suggest that alprazolam-XR has value as a "rescue" as well as a prophylactic or maintenance treatment in panic disorder. These results must be viewed in the context of the study limitations including its small size, the lack of independence of groups in a switch study, and the limitations of the diary records used.

Abrupt discontinuation of alprazolam and cognitive style in patients with panic disorder: early effects on mood, performance, and vital signs

The objective of this study was to ascertain the relationship of alprazolam plasma levels and an anxiety-prone cognitive style to the characteristics and severity of early withdrawal after abrupt discontinuation of alprazolam in 26 patients with panic disorder. After 8 and 9 weeks of fixed-dose treatment, patients were hospitalized for 24 hours. On 1 admission, ordered at random, treatment was maintained; on the other, placebo was substituted double blind. The Anxious Thoughts and Tendencies questionnaire was administered before treatment. Alprazolam plasma levels were measured 7 times on the day after each admission. Before each blood sampling, the Profile of Mood States and performance tasks were administered, and vital signs were recorded. On the day after abrupt discontinuation of alprazolam, Profile of Mood States anxiety, depression, fatigue, and confusion increased; vigor and elation decreased; speed on the digit symbol substitution task improved; and systolic blood pressure increased substantially over time. High Anxious Thoughts and Tendencies scores were related specifically to more anxiety. Our findings (1) confirm that dysphoric mood, fatigue, low energy, confusion, and elevated systolic blood pressure are part of the early syndrome of withdrawal from alprazolam in patients with panic disorder, notably as the drop in plasma levels approaches 50%; (2) indicate a psychomotor deficit persisting beyond dose stabilization; (3) suggest that an anxiety-prone cognitive style measurable before undertaking treatment may be a risk factor for more severe anxiety upon discontinuation; and (4) provide a rationale for applying cognitive behavior therapy during benzodiazepine taper.

Anxiety modulation by the heart? Aerobic exercise and atrial natriuretic peptide

Exercise has an anxiolytic activity and it increases the concentrations of atrial natriuretic peptide (ANP). Because ANP has an anxiolytic activity, this hormone might contribute to the anxiolytic effects of aerobic exercise. Cholecystokinin-tetrapeptide (CCK-4)-induced panic attacks were studied in 10 healthy subjects after "quiet rest" or 30 min of aerobic exercise. Plasma ANP concentrations were measured before and after exercise or quiet rest using a commercial IRMA kit. Compared to quiet rest, CCK-4-induced anxiety was reduced and plasma ANP concentrations were increased by prior exercise. This anxiolytic activity of exercise was correlated with the increase in plasma ANP concentrations. Our results suggest that besides other mechanisms, ANP might be a physiologically relevant humoral link between the heart and anxiety-related behavior contributing to the acute anxiolytic effects of exercise.

[Serum serotonin level in patients with depression and panic attacks]

Serum serotonin level (SSL) was studied using ELISA method in 21 patients with depression associated with panic attacks (PA) and 15 non-depressed patients (8--with PA, 7--with the autonomous nervous system dysfunction). The authors found significant positive correlation between increased SSL and severity of depression, according to BDI (r = 0.82, r < 0.05). There was no correlation with other signs of the disease (anxiety, autonomous nervous system parameters). SSL in control group was about 72.6 +/- 10.06 ng/ml, in mild depressed patients--203.41 +/- 26.47 ng/ml, in severe depressed patients--438.58 +/- 36.31 ng/ml (P(1-2) < 0.001; P(2-3) < 0.001). It was proposed to use SSL for verification the depression severity.

Neuropsychopharmacological properties of neuroactive steroids in depression and anxiety disorders

Neuroactive steroids modulate neurotransmission through modulation of specific neurotransmitter receptors such as gamma-aminobutyric acid type A (GABAA) receptors. Preclinical studies suggested that neuroactive steroids may modulate anxiety- and depression-related behaviour and may contribute to the therapeutical effects of antidepressant drugs. Attenuations of 3alpha-reduced neuroactive steroids have been observed during major depression. This disequilibrium can be corrected by successful treatment with antidepressant drugs. However, non-pharmacological antidepressant treatment strategies did not affect neuroactive steroid composition independently from the clinical response. Further research is needed to clarify whether enhancement of neuroactive steroid levels might represent a new therapeutical approach in the treatment of affective disorders. Nevertheless, the first studies investigating the therapeutical effects of exogenously administered dehydroepiandosterone revealed promising results in the treatment of major depression. In addition, in various anxiety disorders alterations of neuroactive steroid levels have been observed. In panic disorder, in the absence of panic attacks, neuroactive steroid composition is opposite to that seen in depression, which may represent counter-regulatory mechanisms against the occurrence of spontaneous panic attacks. However, during experimentally induced panic attacks, there was a pronounced decline in GABAergic neuroactive steroids, which might contribute to the pathophysiology of panic attacks. In conclusion, neuroactive steroids contribute to the pathophysiology of affective disorders and the mechanisms of action of antidepressants. They are important endogenous modulators of depression and anxiety and may provide a basis for the development of novel therapeutic agents in the treatment of affective disorders.

Brain pH response to hyperventilation in panic disorder: preliminary evidence for altered acid-base regulation

OBJECTIVE

Previous findings of excess brain lactate and delayed end-tidal CO(2) (pCO(2)) recovery in subjects with panic disorder during hyperventilation suggested altered acid-base regulation. Two models were posited to explain these results: 1) subjects with panic disorder demonstrate greater alkalosis to hyperventilation, implicating increased lactate as directly compensatory, or 2) subjects with panic disorder demonstrate reduced or blunted alkalosis, implicating increased lactate as overly compensatory to a normal pH response. In both models, delayed pCO(2) recovery in subjects with panic disorder could reflect slower pH normalization in the recovery phase.

METHOD

Asymptomatic medicated patients with panic disorder were studied during regulated hyperventilation. Phosphorous spectroscopy was used to measure brain pH every 2 minutes. Nine subjects with panic disorder were compared to 11 healthy subjects at baseline (five scans), during regulated hyperventilation (five scans), and across recovery (10 scans). Anxiety symptoms were assessed with standard ratings.

RESULTS

No subject had a panic attack before hyperventilation. Subjects with panic disorder had lower pCO(2) during hyperventilation and slower pCO(2) recovery across the posthyperventilation interval. Despite this different respiratory response in the panic disorder group, brain pH increases were not significantly greater during hyperventilation, nor was pH return to baseline slowed during posthyperventilation. A linear regression model derived from data of healthy subjects showed pH blunting in the panic disorder group.

CONCLUSIONS

Although subjects with panic disorder had greater hypocapnea during hyperventilation, their observed pH response, not altered from comparison levels, implicated exaggerated buffering. It is suggested that increased lactate could account for these findings.

Nitric oxide, adenosine deaminase, xanthine oxidase and superoxide dismutase in patients with panic disorder: alterations by antidepressant treatment

OBJECTIVE

In the present study, we aimed to investigate whether nitric oxide (NO) levels and activities of xanthine oxidase (XO), superoxide dismutase (SOD), and adenosine deaminase (ADA) are associated with Panic disorder (PD) as well as impact of psychopharmacological treatments on NO, SOD, ADA, and XO levels in PD.

METHOD

In this study, 32 patients and 20 healthy controls were included. The serum levels of NO, XO, SOD, and ADA were measured in the patients and controls. The patients were treated with antidepressant.

RESULTS

ADA and XO levels of the patients were significantly higher than the controls. SOD levels of the patients were significantly lower than the controls but the difference was not statistically significant. Although NO levels of the patients were higher than the controls, the difference was not statistically significant. There was no correlation between PAS and the parameters studied (SOD, ADA, XO, and NO) of the patients. After 8 weeks of antidepressant treatment, ADA and SOD activities were increased whereas NO and XO levels decreased significantly.

CONCLUSION

ADA, XO activity may have a pathophysiological role in PD, and prognosis of PD. Activity of these enzymes may be used to monitor effects of the antidepressant treatment.

Increased cholesterol levels after paroxetine treatment in patients with panic disorder

Panic disorder (PD) is associated with an increased cardiovascular risk. We examined serum cholesterol and plasma catecholamine levels in PD before and after paroxetine treatment. The serum cholesterol and plasma catecholamine levels were not different between the PD patients and control subjects before the treatment. However, the levels of total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol were significantly increased in the 28 PD patients after 3 months of paroxetine treatment, whereas the body mass index and plasma catecholamine levels were unchanged. Paroxetine should be used cautiously for PD patients who have overt or covert cardiovascular disorders.

Venlafaxine extended-release capsules in panic disorder: flexible-dose, double-blind, placebo-controlled study

BACKGROUND

Venlafaxine extended-release (ER) has proven efficacy in the treatment of anxiety symptoms in major depression, generalised anxiety disorder and social anxiety disorder.

AIMS

To evaluate the efficacy, safety and tolerability of venlafaxine ER in treating panic disorder.

METHOD

Adult out-patients (n=361) with panic disorder were randomly assigned to receive venlafaxine ER (75-225 mg/day) or placebo for up to 10 weeks in a double-blind study.

RESULTS

Venlafaxine ER was not associated with a greater proportion of patients free from full-symptom panic attacks at the final on-therapy evaluation, but was associated with lower mean panic attack frequency and a higher proportion free from limited-symptom panic attacks, higher response and remission rates, and improvements in anticipatory anxiety, fear and avoidance. Adverse events were comparable with those of the drug in depression and anxiety disorders.

CONCLUSIONS

Venlafaxine ER seems to be effective and well tolerated in the short-term treatment of panic disorder.

Peripheral-type benzodiazepine receptor binding sites in platelets of patients with panic disorder associated to separation anxiety symptoms

RATIONALE

Although it is still a matter of debate whether panic disorder (PD) and separation anxiety (SA) are associated or causally linked disorders, some investigators have suggested that SA may be a specific subtype of panic-agoraphobic spectrum. Several psychiatric disorders, including PD, are associated with lower levels of peripheral-type benzodiazepine receptor (PBR).

OBJECTIVES

The aim of the present study was to evaluate the kinetic binding parameters of the specific PBR ligand, PK 11195, in platelets from patients with PD in relation to the presence and severity of adulthood SA.

METHODS

Using the specific radioligand, [(3)H] PK 11195, the kinetic binding parameters of PBR were determined on platelet membranes of 27 adult outpatients with a DSM-IV diagnosis of PD and 18 healthy controls. Patients were assessed with the SCID-I, the Panic Disorder Severity Scale, the Structured Clinical Interview for Separation Anxiety Symptoms and the Adult Separation Anxiety Checklist.

RESULTS

PD patients had significantly lower PBR density than controls. However, the lower density was only evident in the subgroup of PD patients who also fulfilled the DSM-IV criteria for adult separation anxiety disorder. PBR density was negatively correlated with each of the two SA scales total scores.

CONCLUSIONS

Patients with SA symptoms had significantly lower densities of PBRs. PBR expression might become a useful biological marker of these two associated conditions.

Plasma concentrations of anxiolytic neuroactive steroids in men with panic disorder

Plasma concentrations of neuroactive steroids in men with panic disorder (PD) were measured to evaluate their relations to psychopathology both before and during treatment. Participants comprised 13 men with PD and 10 normal controls. Patients were evaluated while drug-free as well as after 1 and 2 months of paroxetine therapy. Psychopathology was assessed by the State-Trait Anxiety Inventory (STAI), the Panic-Associated Symptom Scale, and the Fear Questionnaire total score. Plasma concentrations of steroids were measured by radioimmunoassay. The plasma concentrations of progesterone and dehydroepiandrosterone were greater in drug-free patients than in controls, whereas those of allopregnanolone and tetrahydrodeoxycorticosterone did not differ between the two groups. Paroxetine treatment for 2 months significantly increased the plasma concentration of allopregnanolone but did not affect those of the other steroids. At 2 months of therapy, allopregnanolone concentrations in patients were significantly greater than those in controls. The plasma concentrations of progesterone and tetrahydrodeoxycorticosterone correlated with the STAI state score in patients before treatment. Our data suggest that neuroactive steroids may play a role in PD in men.

Cognitive Modulation of the Endocrine Stress Response to a Pharmacological Challenge in Normal and Panic Disorder Subjects

CONTEXT

The hypothalamic-pituitary-adrenal (HPA) axis may mediate the deleterious effects of stress on health. It is sensitive to cognitive and emotional aspects of organism-environment interactions, such as familiarity, control, and social support. Scientific study of how such factors moderate human HPA axis activity has been limited. Their relevance to HPA axis disturbances in psychiatric patients is largely unexplored.

OBJECTIVE

To determine whether cognitive manipulation can alter HPA axis activity in laboratory studies and whether patients with panic disorder are differentially sensitive to the manipulated factors.

DESIGN

Pharmacological activation paradigm (cholecystokinin-B agonist pentagastrin) by which we examined symptom and endocrine effects on subjects randomly assigned to a standard introduction or a cognitive intervention.

SETTING

Clinical research center.

PARTICIPANTS

Recruited from university clinic and newspaper advertisements. Fourteen patients with panic disorder and 14 controls, individually matched for age and sex. Intervention Half of each group received a 9-minute cognitive intervention designed to reduce novelty, increase cognitive coping, and provide a sense of control.

MAIN OUTCOME MEASURES

Corticotropin (ACTH) and cortisol levels.

RESULTS

The cognitive intervention significantly reduced cortisol (P = .02) and ACTH (P = .01) levels, despite pentagastrin's robust stimulation of both hormones (P<.001). The intervention effect was evident in patients and controls, who did not differ in basal HPA axis activity or response to pentagastrin. They did differ in panic symptom responses, which were unaffected by the intervention, and in ACTH effects of the intervention. Patients' exaggerated anxiety responses to pentagastrin were normalized by the intervention.

CONCLUSIONS

Cognitive/emotional manipulation can substantially modulate HPA axis responses to pharmacological activation in humans, and HPA disturbances in panic disorder may be secondary to manipulable cognitive/emotional sensitivities. Further study of such factors as novelty, control, and coping may help clarify the origins of HPA axis disturbance in psychiatric disorders and the mediators linking psychosocial stress to disease.

No association of the brain-derived neurotrophic factor (BDNF) gene polymorphisms with panic disorder

Several lines of evidence suggest that genetic factors might contribute to susceptibility to panic disorder. Our previous studies show that the brain-derived neurotrophic factor (BDNF) may play a role in the pathophysiology of major depressive disorders and eating disorders. Assuming that BDNF may be implicated in the putative common pathophysiology of depression and anxiety, we analyzed the association of two BDNF gene single nucleotide polymorphisms (SNPs), 132C > T (formerly named C270T) in the noncoding region of exon V and 196G > A (val66met) in the coding region of exon XIIIA, with panic disorder. In this study, 109 patients with panic disorder diagnosed according to the DSM-IV criteria, and 178 control subjects were recruited. There were no significant differences in the frequency of the genotype or allele in these two SNPs between patients and controls [132C > T in exon V: genotype, p = 1.0, allele, p = 0.59; 196G > A (val66met) in exon XIIIA: genotype, p = 0.77, allele, p = 0.78]. Furthermore, no significant associations of agoraphobia with the two SNPs were detected. This study suggests that the BDNF gene polymorphisms are not associated with panic disorder in our Japanese population.

Twenty-four hour growth hormone secretion in patients with panic disorder

BACKGROUND

Patients with panic disorder have blunted growth hormone (GH) responses to clonidine, suggesting subsensitivity of post-synaptic alpha(2)-adrenoreceptors, presumably in response to excessive central noradrenergic outflow. However, basal levels of GH release over a full circadian cycle have not been examined in panic. Reduced basal GH release would suggest an overall hypo-active GH system rather than a specific alpha-adrenergic abnormality.

METHODS

To determine whether panic patients show reduced basal GH secretion, 20 patients and 12 healthy controls were studied. Blood samples were drawn every 15 min for 24 h and plasma was assayed for GH. Patients were restudied during successful treatment with alprazolam. Groups were compared on overnight and daytime GH secretion and circadian patterns of release.

RESULTS

Patients showed normal levels on all measures of GH release. Treatment may have reduced nocturnal GH release slightly, but treated patients still did not differ from controls. The normal predominance of sleep over waking GH secretion was seen in both groups.

CONCLUSIONS

Panic patients, in contrast to depressed patients, have normal somatotrophic axis activity when measured in a resting state over a full circadian cycle. GH dysregulation may only be evident in these patients in activation paradigms and has been most consistently demonstrated by challenges with the alpha(2)-noradrenergic agonist, clonidine.

Metyrapone tests in patients with panic disorder

BACKGROUND

Studies of hypothalamic secretion of corticotropin-releasing hormone (CRH) in patients with panic disorder in the nonpanic state (using CRH tests) are contradictory. No data about the hypothalamic-pituitary response to metyrapone are available.

METHODS

Study participants included 14 patients with panic disorder (DSM-IV criteria) and 14 healthy control subjects who underwent a standard overnight metyrapone test and a combined metyrapone/low-dose dexamethasone test.

RESULTS

Significant treatment effects of metyrapone and combined metyrapone/dexamethasone were found on plasma corticotropin, cortisol, and 11-deoxycortisol, but no differences between patients and control subjects emerged. Considering visual analogue scale ratings of anxiety, tension, restlessness, and Beck Depression Inventory scores as covariates, no group effects were detected.

CONCLUSIONS

Standard overnight metyrapone tests do not support a hypersecretion of hypothalamic CRH in panic disorder. Furthermore, no evidence for increased glucocorticoid negative feedback in panic was found. Hypothalamic CRH secretion in the nonpanic state needs further research.

Serotonin-mediated phosphorylation of extracellular regulated kinases in platelets of patients with panic disorder versus controls

Phosphorylation of extracellular signal-regulated kinases (ERK 1/2) represents a converging intracellular signalling pathway which is involved in the modulation of gene transcription and may contribute to the feed-back regulation of neurotransmitter receptor functioning. The purpose of the current study was to investigate the serotonin-mediated phosphorylation of ERK 1/2 in platelets from patients (n = 17) with panic disorder, with respect to healthy volunteers (n = 17). Patients presented a severe symptomatology as assessed by the self-report rating scales for panic-agoraphobic (PAS-SR) and mood (MOOD-SR) spectrum, and by Clinical Global Impression Severity Scale (CGI-S). In platelets from healthy volunteers, serotonin induced a rapid increase of ERK 1/2 phosphorylation with a transient monophasic kinetic. The dose-response curves showed this effect was concentration dependent with an average of the EC(50) value of 22.8 +/- 2.4 microM. Platelet pre-incubation with 5HT(1A) and 5HT(2A) antagonists, pindobind and ritanserin, significantly inhibited serotonin-mediated kinase activation with an EC(50) of 3.2 +/- 0.2 and 1.99 +/- 0.08 nM, respectively, suggesting an involvement of these specific receptor subtypes in serotonin-mediated response. Furthermore, the 5HT(1A) and 5HT(2A) agonists, 8-hydroxy-N,N-dipropyl-aminotetralin (8OH-DPAT) and 1-(2,5-dimethoxy)-4-iodophenyl-2-aminopropane (DOI), were able to modulate ERK 1/2 phosphorylation in a concentration-dependent manner with an EC(50) value of 3.1 +/- 0.2 and 76 +/- 4.5 nM, respectively. ERK 1/2 phosphorylation was not observed after serotonin treatment of platelets from drug-free panic disorder patients, suggesting an alteration in intracellular phosphorylative pathways. Since ERK 1/2 responsiveness to other stimulus, such as collagen and thrombin, was comparable in platelets from healthy volunteers and patients, our results suggested that a specific alteration of serotonergic system occurred in panic disorder. Further studies to investigate 5HT(1A) and 5HT(2A) receptor expression and threonine phosphorylation levels showed that, nevertheless no significant differences in the receptor expression levels were detected, an increase of both 5HT receptor phosphorylation, on threonine residues, occurred in platelet from panic patients with respect to controls, suggesting that a reduction of serotonin receptor functioning was involved in the loss of serotonin responsiveness in panic.

Serum lipid levels, suicidality, and panic disorder

Although the effects of serum total cholesterol and other lipids have been implicated as a predictor of suicidal behavior in major depression, the role of cholesterol level on suicide risk for panic disorder patients is not considered as a biological marker in the literature. In this study, we examined the relationship of suicidality with serum cholesterol concentration in panic disorder. The subjects of the study were 10 suicidal panic disorder patients, 19 nonsuicidal panic disorder patients, and 15 normal control subjects. The suicidal patients with panic disorder had lower serum total cholesterol and low-density lipoprotein (LDL) levels than normal control subjects. These findings suggest that there may be an association between suicidality and low serum cholesterol levels in panic disorder. We also discuss the possible role of serotonin in the brain in the relationship of suicidal behavior or ideation with low cholesterol concentration in panic disorder.

Effects of exposure to selective serotonin reuptake inhibitors during pregnancy on serotonergic symptoms in newborns and cord blood monoamine and prolactin concentrations

BACKGROUND

Selective serotonin reuptake inhibitors (SSRIs) have gained wide acceptance in the treatment of mental disorders in pregnant women, but there seems to be an increased risk for neonatal adaptation problems after exposure to SSRIs in late pregnancy. We aimed to investigate the perinatal sequelae of infants exposed to SSRIs during their fetal life and the relationship of these symptoms to the cord blood monoamine and prolactin concentrations.

METHODS

We conducted a prospective, controlled, follow-up study with 20 mothers taking 20 to 40 mg/d of either citalopram or fluoxetine for depression (n = 10) or panic disorder (n = 10) and their infants and 20 matched controls not receiving psychotropic medication for confounding obstetric characteristics. Maternal cord blood and infant citalopram, fluoxetine, and norfluoxetine, cord blood monoamine and metabolite, and prolactin concentrations were measured. The newborns underwent standard clinical examination and specific assessment of serotonergic symptoms during the first 4 days of life and at the ages of 2 weeks and 2 months.

RESULTS

There was a statistically significant (P =.008, V = 15, n = 20 for both groups), 4-fold difference in the serotonergic symptom score during the first 4 days of life between the SSRI group and the control group. The SSRI-exposed infants had significantly lower cord blood 5-hydroxyindoleacetic acid (5-HIAA) concentrations (P =.02, t31 = 2.57) compared with the control group. A significant inverse correlation (rs = -0.66, P =.007, n = 15) was seen between the serotonergic symptom score and the umbilical vein 5-HIAA concentrations in the SSRI-exposed but not the control infants.

CONCLUSIONS

Infants exposed to SSRIs during late pregnancy are at increased risk for serotonergic central nervous system adverse effects, and the severity of these symptoms is significantly related to cord blood 5-HIAA levels.

Neurosteroid secretion in panic disorder

Evidence that neurosteroids have anxiolytic effects in animal models of anxiety has suggested that alterations of neurosteroid secretion might be implicated in the pathogenetic mechanisms of anxiety disorders in humans. In 25 female patients with panic disorder (PD) and 11 healthy female controls, we measured plasma concentrations of progesterone (PROG), pregnenolone (PREG), allopregnanolone (3alpha,5alpha-tetrahydroprogesterone=3alpha,5alpha-THPROG), dehydroepiandrosterone (DHEA) and tetrahydrodeoxycorticosterone (3alpha,5alpha-THDOC) during a drug-free month and during the following month of paroxetine therapy. The neurosteroids were measured during the early follicular phase, the mid-luteal phase and the premenstrual phase of both months (days 7, 22 and 27 from the beginning of the cycle). Significantly higher levels in patients than controls were found in PROG during the mid-luteal phase of both months, PREG in the premenstrual phase in the drug-free month, 3alpha,5alpha-THPROG during the follicular phase of the drug-free month and during the premenstrual phase of the therapy month, and 3alpha,5alpha-THDOC during the premenstrual phases of both months. DHEA levels did not differ in patients and controls. These results suggest that neurosteroids in PD are hypersecreted, possibly as an attempt to counteract the anxiogenic underlying hyperactivity of the hypothalamo-pituitary-adrenal axis and to improve a reduced GABA(A) receptor sensitivity.

Antioxidant enzyme and malondialdehyde levels in patients with panic disorder

There is evidence of an etiopathogenetic role of free radicals (FRs) in some neuropsychiatric disorders. The aim of the present study was to determine whether the activity levels of some antioxidant enzymes [glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT)] and malondialdehyde (MDA), a product of lipid peroxidation, were associated with panic disorder (PD). Twenty patients diagnosed with PD and 20 healthy controls were enrolled in this study. A clinical evaluation and measurements of GSH-Px SOD, CAT and MDA were performed. Additionally, all patients were assessed by the Panic Agoraphobia Scale (PAS). The mean GSH-Px, SOD and MDA levels of the patient group were significantly higher than those of the controls. There was a significant positive correlation between PAS scores and GSH-Px, SOD and MDA levels and between the duration of illness and SOD, CAT and MDA levels in the patient group. In conclusion, our results suggest that FRs may be involved in PD.

Sympathetic reactivity in agoraphobic patients with and without personality disorders

OBJECTIVE

To compare sympathetic activity in agoraphobic patients with and without personality disorders before and after 11 weeks inpatient treatment.

METHODS

Agoraphobic patients (n=38), 84% with panic disorder and 47% with personality disorders underwent cold pressure test (CPT), mental stress test (MST), and a specific anxiety test (SAT). Psychological assessments were done by the Bodily Sensations Questionnaire (BSQ), the Agoraphobic Cognitions Questionnaire (ACQ), Spielberger STAI-1 and -2, and a Stress Test Anxiety (STA) questionnaire. Sympathetic activity was measured by blood pressure, heart rate, epinephrine, and norepinephrine.

RESULTS

The sympathetic activity did not differ significantly between patient groups, and the reactivity to stress was very low. The sympathetic reactivity remained unchanged after treatment, whereas psychiatric symptoms decreased. Correlations between sympathetic activity and psychological distress were not significant.

CONCLUSION

Interpretation of bodily signals seems to be more important than the actual sympathetic activity in agoraphobic patients.

Stress regulates the lymphocyte homing receptor CD62L (L-selectin)

Based on a previous study showing that panic disorder patients had increased expression of na ve phenotype lymphocytes (CD45RA+ and CD62L+), increased plasma cortisol, as well as decreased interleukin-2 (IL-2) producion, we hypothesized that changes in the percentage of expression of these lymphocyte surface molecules could be related to the substances released by the hypothalamic-pituitary-adrenal (HPA) axis and possibly associated to panic disorder (cortisol, IL-2, serotonin and epinephrine). In order to study the altered expression, blood mononuclear cells of normal volunteers were stimulated with mitogen, in the presence of dexamethasone, IL-2, serotonin and epinephrin. CD62L is decreased by IL-2 in vitro. Serotonin and epinephrine did not promote changes in the expression of these surface molecules. The results of the ex vivo study are in agreement with a previous clinical study with panic patients. It could be suggested that stress is responsible for certain immunologic dysfunctions and new studies should be conducted.

Induced panic attacks shift gamma-aminobutyric acid type A receptor modulatory neuroactive steroid composition in patients with panic disorder: preliminary results

BACKGROUND

Certain metabolites of progesterone such as 3alpha,5alpha-tetrahydroprogesterone (3alpha,5alpha-THP; allopregnanolone) and 3alpha,5beta-THP (pregnanolone) are potent, positive allosteric modulators of gamma-aminobutyric acid type A receptors. Although animal studies suggest anxiolytic properties of these endogenous modulators of central nervous excitability, no clinical data indicate whether they are also involved in the pathophysiology of anxiety disorders and panic attacks.

METHODS

We quantified the concentrations of 3alpha,5alpha-THP, 3alpha,5beta-THP, the isomer 3beta,5alpha-THP, and their precursors in the plasma of 10 patients with panic disorder and matched control subjects during panic attacks induced by means of sodium lactate and cholecystokinin tetrapeptide administration, using a highly sensitive gas chromatography-mass spectrometry analysis.

RESULTS

Panic attacks induced by sodium lactate and cholecystokinin tetrapeptide in patients with panic disorder were accompanied by pronounced decreases in the concentrations of 3alpha,5alpha-THP and 3alpha,5beta-THP and a concomitant increase in the concentrations of the functional antagonistic isomer 3beta,5alpha-THP, findings that are compatible with a decreased gamma-aminobutyric acid-ergic tone. No changes in neuroactive steroid concentrations were observed after placebo administration in patients with panic disorder or after placebo, sodium lactate, or cholecystokinin tetrapeptide administration in controls.

CONCLUSIONS

The association between changes in plasma neuroactive steroid concentrations and experimentally induced panic attacks and the well-documented pharmacological properties of these compounds as gamma-aminobutyric acid type A receptor modulators suggest that neuroactive steroids may play a role in the pathophysiology of panic attacks in patients with panic disorder.

Pentagastrin-induced sleep panic attacks: panic in the absence of elevated baseline arousal

BACKGROUND

It has been suggested that pharmacological challenges that induce panic attacks are confounded by effects of environmental stress, elevated baseline arousal, and expectancy bias.

METHODS

To control for effects of arousal and cognition on the panicogenic effects of pentagastrin, pharmacological challenges were conducted during sleep in seven patients with panic disorder or social phobia. All patients had previously experienced pentagastrin-induced panic while awake. Infusions of normal saline and pentagastrin (0.6 microg/kg) were administered in fixed order and timed so that pentagastrin infusions took place during the transition from Stage 2 to Stage 3 sleep. Long intravenous lines were placed for remote blood sampling and subsequent analysis of plasma adrenocorticotropic hormone and cortisol. Measures of anxiety and panic were obtained at baseline and upon awakening after pharmacological challenge.

RESULTS

All seven subjects awoke within seconds following pentagastrin infusion. Four patients reported symptoms that met criteria for panic. Neither baseline anxiety nor neuroendocrine measures were predictive of panic.

CONCLUSIONS

These data demonstrate the ability to induce panic during a period of diminishing arousal and indicate that panic attacks can occur in the absence of elevated arousal and environmental stress.

The protein kinase A in platelets from patients with panic disorder

Although previous studies suggested that dysfunctions in the protein kinase A (PKA) and in some of its substrates are associated with several psychiatric disorders, there is no evidence regarding the possible involvement of such components in panic disorder (PD). Thus, the aim of the present study was to investigate the levels of PKA and Rap1 in platelets from patients with such disorder. Twenty-four drug free patients with PD and 24 healthy volunteers participated to the study. Employing the Western Blot analysis, immunostaining and computer-assisted imaging, the levels of the regulatory (R, type I and type II) and the catalytic (C) subunits of PKA, and those of Rap1 were assessed in platelets from the two groups. The data show that patients with PD have significantly higher levels of platelet RI and C subunits of PKA than controls, whereas the levels of RII were unchanged. No significant differences were found in the immunolabelling of Rap1 between groups. These findings may provide clues toward understanding the involvement of cAMP signalling in anxiety disorders.

Aging and panicogenic response to cholecystokinin tetrapeptide: an examination of the cholecystokinin system

Older age is associated with diminished symptomatic and cardiovascular response to the panicogenic agent cholecystokinin tetrapeptide (CCK-4). We hypothesized that circulating concentrations of endogenous CCK-4 and/or CCK-8 are increased in later life, possibly due to decreased enzymatic degradation, and that this is associated with desensitization of CCK-B receptors. The study group consisted of 20 healthy subjects aged 18-30 years and 20 healthy subjects aged 65-85 years. The two groups were compared on fasting basal plasma concentrations of CCK-4, sulfated CCK-8 (CCK-8s) and nonsulfated CCK-8 (CCK-8 ns), and on binding capacity of lymphocyte CCK-B receptors. Under single-blind (to subject) conditions, subjects were then administered an intravenous bolus of placebo, followed 50 min later by an intravenous bolus of 50 micro g of CCK-4. Plasma concentrations of total CCK (CCK(T)) were measured 2 min before and 2, 5, 10, and 15 min after each injection. Compared with younger subjects, older subjects had a significantly higher basal plasma concentration of CCK-8s and significantly diminished binding capacity of CCK-B receptors. Following injection of placebo, plasma CCK(T) concentrations did not significantly change from baseline in either age group, but the elderly had significantly higher concentrations than the young at 2, 5, and 10 min. Following injection of CCK-4, the plasma concentration of CCK(T) was highest at 2 min and declined after that. The elderly had significantly higher CCK(T) concentrations (ie. a slower decline in CCK(T)) than the young at 5, 10, and 15 min. These findings are consistent with our hypothesis and suggest that age-related changes in the CCK system could contribute to the diminished panicogenic response to exogenous CCK-4 in older persons.

Memory performance in panic disorder patients after chronic use of clomipramine

This study investigated the chronic use (6.3 +/- 0.5 years; mean +/- SEM) of therapeutic doses of clomipramine (57.0 +/- 8.0 mg/day) by outpatients with panic disorder/agoraphobia who were currently in remission to assess impairment of memory and psychomotor functions. In addition, the association between test performance and serum levels of clomipramine (CMI) and its active metabolite desmethylclomipramine (DCMI) was also assessed. Patients and healthy volunteers matched for sex, age and educational level were submitted to rating scales and to memory and psychomotor tests. There was no significant difference between groups regarding any variable, except for metamemory. Significant associations were found between (i) longer-term clomipramine treatment and poorer performance in the implicit test and (ii) higher serum levels of clomipramine or desmethylclomipramine, or both (CMI + DCMI) and lower performance in central executive tests and metamemory. The results showed that low doses of CMI chronically administered to panic patients are associated with diminished metamemory and impaired priming and working memory. Further investigations are needed to confirm these results and to determine whether the chronic use of higher therapeutic doses of tricyclic antidepressants is associated with more intense deleterious effects on memory and psychomotor functions.

Effect of citalopram treatment on relationship between platelet serotonin functions and the Karolinska scales of personality in panic patients

Using the Karolinska Scales of Personality (KSP), we investigated the effect of the selective serotonin reuptake inhibitor citalopram on personality traits and the relationship between personality traits and peripheral indexes for central serotonergic function in patients with panic disorder at baseline and after 6 months of treatment. The degree of anxiety and depression was assessed using the Beck Anxiety Inventory, the Beck Depression Inventory, the Clinical Anxiety Scale, and the Montgomery Asberg Depression Rating Scale. A reduction in anxiety and depression scores of 75% was observed after treatment in two thirds of the patients. Mean changes of 12% in the direction of normalization were observed in all KSP anxiety-related items (Somatic Anxiety, Muscular Tension, Psychic Anxiety, and Psychasthenia), the aggression and hostility related items (Inhibition of Aggression, Irritability, and Guilt) and the item of Socialisation. A positive correlation was found between Vmax for the platelet [14C]-serotonin uptake and Inhibition of Aggression before treatment, and a negative correlation was found between the affinity of serotonin uptake and Inhibition of Aggression after treatment. Negative childhood experiences influenced enhanced scores on some KSP items but not the serotonergic function. In panic patients treated with citalopram, effects were seen on personality traits, confirming an association between serotonergic activity and aggression.

Serum cholesterol level comparison: control subjects, anxiety disorder patients, and obsessive-compulsive disorder patients

OBJECTIVE

To determine whether panic disorder is associated with elevated serum cholesterol levels. Serum cholesterol levels of panic disorder patients are reported to be elevated. This could explain the higher-than-expected cardiovascular mortality in this population. Some evidence exists wherein cholesterol levels are also increased in patients with general anxiety disorder and phobias. To date, there are only 2 reports on cholesterol levels of obsessive-compulsive disorder (OCD) patients, giving controversial results.

METHOD

We compared serum cholesterol levels of anxiety disorder patients, OCD patients, and normal control subjects with each other (n = 60 in each group). Serum cholesterol was measured in each subject before treatment. Subjects of the 3 groups were matched by age and sex.

RESULTS

Patients with anxiety disorders and OCD had elevated cholesterol levels, compared with normal control subjects. Cholesterol levels in OCD patients were comparable with those in patients with phobia.

CONCLUSIONS

Our data support the assumption that elevation in cholesterol level is not a specific feature of panic disorder (as most assumed), but more generally associated with anxiety disorders. Increased cholesterol levels in patients with anxiety disorders and OCD may be of clinical relevance.

Prolactin but not ACTH increases during sodium lactate-induced panic attacks

Paradoxically, the pituitary-adrenal axis is not activated during sodium lactate-induced panic. We measured the response of another stress-sensitive hormone, prolactin, to standard lactate and placebo infusion in a double-blind randomised design in eight patients with panic disorder and eight matched normal controls. Prolactin release was significantly elevated (P < 0.05) in panickers compared with non-panickers, whereas ACTH secretion was not activated at all. This differential stress response needs further investigation.