Clinical similarity and biological diversity in the response to alprazolam in patients with panic disorder and generalized anxiety disorder

Heart rate variability in generalized anxiety disorder, major depressive disorder and panic disorder: A network meta-analysis and systematic review

BACKGROUND

Heart rate variability (HRV) in patients with emotional disorders and healthy controls (HCs) has been investigated in many studies but the difference between these emotional disorders was unclear.

METHODS

The PubMed, Embase, Medline and Web of Science databases were systematically searched for studies published in English that compared HCs with generalized anxiety disorder (GAD), major depressive disorder (MDD), panic disorder (PD) patients in HRV. We conducted a network meta-analysis to compare HRV in patients with GAD, MDD, PD and HCs. HRV outcomes, including time domain indices (the standard deviation of NN intervals (SDNN) and the root mean square of the successive differences between normal heartbeats (RMSSD)), and frequency domain indices (High-frequency (HF), Low-frequency (LF) and the ratio of LF to HF (LF/HF)) were obtained. A total of 4008 participants from 42 studies were included.

RESULTS

The results of pairwise meta-analysis showed that compared with controls, GAD, PD and MDD patients exhibited significantly reduced HRV. Similar findings were also confirmed in network meta-analysis. The most important finding from network meta-analysis was that GAD patients had significantly lower SDNN than PD patients (SMD = -0.60, 95 % CI [-1.09, -0.11]).

CONCLUSION

Our findings provided a potential objective biological marker to distinguish between GAD and PD. In the future, a large sample of research is needed to directly compare HRV of various mental disorders, which is crucial for finding biomarkers to distinguish them.

Effects of Oral Administration of Alprazolam and Lorazepam as Hypnotics on Cardiovascular Parameters in Hypertensive Patients

BACKGROUND

Previous studies have suggested that evening intake of benzodiazepine affects blood pressure (BP) and/or heart rate (HR) in healthy and hypertensive subjects. The aim of this study was to compare the effect of chronic oral administration of alprazolam and lorazepam as hypnotics on ambulatory BP and HR in patients with mild hypertension.

METHODS

Consecutive outpatients of both sexes with newly diagnosed, never-treated mild hypertension were randomized, after a 4-week placebo run-in period, to receive alprazolam 0.5 mg plus placebo, lorazepam 1 mg plus placebo, or placebo plus placebo for 2 weeks in 3 crossover periods, each separated by a 1-week placebo wash-out period. At the end of the initial placebo run-in and of each treatment period, 24-hour ambulatory BP and HR monitoring was performed using a noninvasive device.

RESULTS

In the 32 patients, no treatment had any effect on 24-hour and daytime systolic BP (SBP), diastolic BP (DBP), and HR, which remained unchanged. During the nighttime, SBP and DBP values were unaffected by alprazolam, as compared with placebo, whereas DBP was significantly higher after treatment with lorazepam (+3.7%, P < 0.05 vs placebo). Nocturnal HR mean values were significantly increased by lorazepam (+10.1%, P < 0.01 vs placebo), whereas they did not change after alprazolam.

CONCLUSIONS

In patients with mild hypertension, oral intake of alprazolam or lorazepam as hypnotics did not affect ambulatory BP or HR values. A slight increase in nighttime DBP was observed with lorazepam, whereas alprazolam showed no effect on nocturnal BP and HR, probably reflecting a stimulating effect of the drug on central α2-receptors.

The hypothalamus in anxiety disorders

Of all mental disorders, anxiety disorders are currently the strongest contributors to the global burden of disease, with 7.3% of the general population affected worldwide. The hypothalamus is crucial hub of a network of neural structures modulating fear conditioning and extinction and, as such, highly relevant to the pathophysiology of these conditions. Three hypothalamic systems have emerged as particularly relevant in this context. First, the oxytocin system is highly likely to be involved anxiety disorders and in particular in the cognitive and behavioral deficits pertaining to social anxiety disorder. Second, peripheral markers of the hypothalamic-pituitary-adrenal axis appear altered in patients with panic disorder and generalized anxiety disorder, which may denote aberrant functioning of their central corticotropin-releasing hormone system. Furthermore, cortisol seems to augment the effects of exposure therapy in patients with specific phobia. Third, the integrity of the hypothalamic-pituitary-thyroid axis is likely compromised in panic disorder. Further, cross-disciplinary research efforts are required to shed more light on how, exactly, these hypothalamic systems interact with the neural structures involved in fear conditioning and extinction, which should ultimately open up new avenues for the prevention and treatment of anxiety disorders.

Peripheral Biomarkers in DSM-5 Anxiety Disorders: An Updated Overview

Anxiety disorders are prevalent and highly disabling mental disorders. In recent years, intensive efforts focused on the search for potential neuroimaging, genetic, and peripheral biomarkers in order to better understand the pathophysiology of these disorders, support their diagnosis, and characterize the treatment response. Of note, peripheral blood biomarkers, as surrogates for the central nervous system, represent a promising instrument to characterize psychiatric disorders, although their role has not been extensively applied to clinical practice. In this report, the state of the art on peripheral biomarkers of DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th edition) Anxiety Disorders is presented, in order to examine their role in the pathogenesis of these conditions and their potential application for diagnosis and treatment. Available data on the cerebrospinal fluid and blood-based biomarkers related to neurotransmitters, neuropeptides, the hypothalamic-pituitary-adrenal axis, neurotrophic factors, and the inflammation and immune system are reviewed. Despite the wide scientific literature and the promising results in the field, only a few of the proposed peripheral biomarkers have been defined as a specific diagnostic instrument or have been identified as a guide in the treatment response to DSM-5 Anxiety Disorders. Therefore, further investigations are needed to provide new biological insights into the pathogenesis of anxiety disorders, to help in their diagnosis, and to tailor a treatment.

Biological markers of generalized anxiety disorder

Generalized anxiety disorder (GAD) is a prevalent and highly disabling mental health condition; however, there is still much to learn with regard to pertinent biomarkers, as well as diagnosis, made more difficult by the marked and common overlap of GAD with affective and anxiety disorders. Recently, intensive research efforts have focused on GAD, applying neuroimaging, genetic, and blood-based approaches toward discovery of pathogenetic and treatment-related biomarkers. In this paper, we review the large amount of available data, and we focus in particular on evidence from neuroimaging, genetic, and neurochemical measurements in GAD in order to better understand potential biomarkers involved in its etiology and treatment. Overall, the majority of these studies have produced results that are solitary findings, sometimes inconsistent and not clearly replicable. For these reasons, they have not yet been translated into clinical practice. Therefore, further research efforts are needed to distinguish GAD from other mental disorders and to provide new biological insights into its pathogenesis and treatment.

Biological markers for anxiety disorders, OCD and PTSD: A consensus statement. Part II: Neurochemistry, neurophysiology and neurocognition

OBJECTIVE

Biomarkers are defined as anatomical, biochemical or physiological traits that are specific to certain disorders or syndromes. The objective of this paper is to summarise the current knowledge of biomarkers for anxiety disorders, obsessive-compulsive disorder (OCD) and posttraumatic stress disorder (PTSD).

METHODS

Findings in biomarker research were reviewed by a task force of international experts in the field, consisting of members of the World Federation of Societies for Biological Psychiatry Task Force on Biological Markers and of the European College of Neuropsychopharmacology Anxiety Disorders Research Network.

RESULTS

The present article (Part II) summarises findings on potential biomarkers in neurochemistry (neurotransmitters such as serotonin, norepinephrine, dopamine or GABA, neuropeptides such as cholecystokinin, neurokinins, atrial natriuretic peptide, or oxytocin, the HPA axis, neurotrophic factors such as NGF and BDNF, immunology and CO2 hypersensitivity), neurophysiology (EEG, heart rate variability) and neurocognition. The accompanying paper (Part I) focuses on neuroimaging and genetics.

CONCLUSIONS

Although at present, none of the putative biomarkers is sufficient and specific as a diagnostic tool, an abundance of high quality research has accumulated that should improve our understanding of the neurobiological causes of anxiety disorders, OCD and PTSD.

Hypothalamic-pituitary-adrenocortical axis: neuropsychiatric aspects

Evidence of aberrant hypothalamic-pituitary-adrenocortical (HPA) activity in many psychiatric disorders, although not universal, has sparked long-standing interest in HPA hormones as biomarkers of disease or treatment response. HPA activity may be chronically elevated in melancholic depression, panic disorder, obsessive-compulsive disorder, and schizophrenia. The HPA axis may be more reactive to stress in social anxiety disorder and autism spectrum disorders. In contrast, HPA activity is more likely to be low in PTSD and atypical depression. Antidepressants are widely considered to inhibit HPA activity, although inhibition is not unanimously reported in the literature. There is evidence, also uneven, that the mood stabilizers lithium and carbamazepine have the potential to augment HPA measures, while benzodiazepines, atypical antipsychotics, and to some extent, typical antipsychotics have the potential to inhibit HPA activity. Currently, the most reliable use of HPA measures in most disorders is to predict the likelihood of relapse, although changes in HPA activity have also been proposed to play a role in the clinical benefits of psychiatric treatments. Greater attention to patient heterogeneity and more consistent approaches to assessing treatment effects on HPA function may solidify the value of HPA measures in predicting treatment response or developing novel strategies to manage psychiatric disease.

Investigation of cortisol levels in patients with anxiety disorders: a structured review

Anxiety disorders are common and distressing medical conditions, which typically arise in adolescence or early adult life. They can persist for many years, reducing quality of life, limiting academic and occupational achievement, and being responsible for considerable economic pressures. Although a range of psychological and pharmacological treatments are available, their success is often limited, and many patients remain troubled by significant symptom-related disability for long periods. The detailed pathophysiology of each anxiety disorder is not established, and novel treatments that are based solely on current understanding of conventional neurotransmitter function are unlikely to be substantially more effective or better tolerated than current treatments. Investigations of hypothalamo-pituitary axis function across panic disorder, generalized anxiety disorder, specific phobias and social anxiety disorder have produced intriguing findings but not revealed a consistent pattern of endocrine disturbance, perhaps reflecting differences in methodology and the nature and size of the clinical samples. There is a persistent need for large, prospective studies using standardized methods for investigation and data analysis (164 words).

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

RATIONALE

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

OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Generalized anxiety disorder and its comorbidities: disputes at the boundaries

This theoretical paper reviews the status of generalized anxiety disorder (GAD) and the Axis I and Axis II disorders with which it is often comorbid. Differences in comorbidity between the epidemiological and clinical literatures are discussed. Special attention is given to panic disorder, the symptoms of which are similar to those of GAD. The boundaries of GAD and its relationship to other Axis I disorders and to Axis II disorders raise important implications for its classification.