Generalized anxiety disorder: between now and DSM-V

Overshadowed by the amygdala: the bed nucleus of the stria terminalis emerges as key to psychiatric disorders

The bed nucleus of the stria terminalis (BNST) is a center of integration for limbic information and valence monitoring. The BNST, sometimes referred to as the extended amygdala, is located in the basal forebrain and is a sexually dimorphic structure made up of between 12 and 18 sub-nuclei. These sub-nuclei are rich with distinct neuronal subpopulations of receptors, neurotransmitters, transporters and proteins. The BNST is important in a range of behaviors such as: the stress response, extended duration fear states and social behavior, all crucial determinants of dysfunction in human psychiatric diseases. Most research on stress and psychiatric diseases has focused on the amygdala, which regulates immediate responses to fear. However, the BNST, and not the amygdala, is the center of the psychogenic circuit from the hippocampus to the paraventricular nucleus. This circuit is important in the stimulation of the hypothalamic-pituitary-adrenal axis. Thus, the BNST has been largely overlooked with respect to its possible dysregulation in mood and anxiety disorders, social dysfunction and psychological trauma, all of which have clear gender disparities. In this review, we will look in-depth at the anatomy and projections of the BNST, and provide an overview of the current literature on the relevance of BNST dysregulation in psychiatric diseases.

Prevalence and clinical characteristics of remission during treatment in generalized anxiety

OBJECTIVE

Although the remission criteria for generalized anxiety are well defined, there is not much data available on the point prevalence of remission. The Measuring Impact of Remission in Anxiety Disorders in Belgium (MIRABEL) study is a naturalistic study designed to document the point prevalence of remission in patients treated for general anxiety and potential factors affecting this prevalence.

METHODS

The study population consisted of 618 adult outpatients being treated for generalized anxiety. The sample is defined by the key symptoms of generalized anxiety disorder rather than by fulfilling the exact DSM-IV-TR diagnostic criteria. Remission was defined as a Hamilton Anxiety Scale (HAM-A) score of less than or equal to 7. To reduce the interrater reliability, the HAM-A was assessed by the attending physicians who had no specific training. Factors investigated as possibly related to remission included sociodemographic, disease and treatment characteristics.

RESULTS

The point prevalence of remission in the study population was estimated at 13.3%. Remission prevalence varied with occupational status and severity of the current anxiety episode. Remission prevalence was lower in the presence of comorbidity and was proportional to the number of comorbid symptoms. Remitters took fewer medications but were treated longer. Remission prevalence was higher in patients who were taking antidepressants, but was lower in patients who were taking sedatives.

CONCLUSIONS

These findings underline the poor prognosis of generalized anxiety.

Pharmacological treatment of generalized anxiety disorder

INTRODUCTION

Generalized anxiety disorder (GAD) is a chronic, relapsing, debilitating disorder, associated with markedly impaired social and occupational functioning. Pharmacological treatment is considered standard care and several drug classes are now FDA approved for the treatment of GAD. While there are clear data for the efficacy of short-term acute treatment, long-term treatment and treatment-resistant GAD remain challenging.

AREAS COVERED

This article describes current pharmacological treatment options for GAD, with focus on benzodiazepines, azapirones, antidepressants and anticonvulsant and antipsychotic drugs. Recent findings from placebo-controlled clinical trials are reviewed and evidence-based clinical implications are discussed. A PubMed search was completed using the terms: 'generalized anxiety disorder AND treatment' and 'generalized anxiety disorder AND therapy'. Additional pivotal trials were included for a historical perspective (older landmark trials that established efficacy and safety for older drug classes in the treatment of GAD).

EXPERT OPINION

Efficacy for treatment of GAD has been established for several different drug classes. At present, based on clear efficacy and good tolerability, first-line treatment with either a selective serotonin reuptake inhibitor (SSRI) or a serotonin-norepinephrine reuptake inhibitor (SNRI) is indicated. If an initial, at least moderate, clinical response is achieved under antidepressant therapy, treatment should be at least continued for 12 months.

An open, non-randomised comparison of escitalopram and duloxetine for the treatment of subjects with Generalized Anxiety Disorder

OBJECTIVES

This study compares the effectiveness of a 6-months treatment with escitalopram (ESC), a selective serotonin reuptake inhibitor, or duloxetine (DUL), a balanced serotonin and nor-adrenaline reuptake inhibitor, in 43 subjects with Generalized Anxiety Disorder (GAD).

METHODS

Assessment was made with the Hamilton Anxiety and Depression scales (HAM-A; HAM-D), with the CGI, and with the GAF at T0 (intake), T1, T3, T6 (1, 3, and 6 months later). The comparison among the two treatment groups (ESC=20; DUL=23) at the four endpoints was made through a GLM-ANOVA for repeated measures. Rates of remission (HAM-A<7), response (HAM-A reduction of 50% or above) and dropout were evaluated.

RESULTS

At 1, 3, and 6 months after treatment inception both treatment groups showed a significant improvement in the scores of CGI, HAMA, HAM-D, and GAF, and an equivalent rate of dropout. The DUL group registered a greater amount of remission and response rates at T1 against the ESC group in all the scales except in the HAM-D scale. Duloxetine was more effective than escitalopram after the first month of treatment only in the somatic subscale of HAM-A. The presence of a cluster C personality disorder was associated in both groups to greater difficulties in attaining remission and to dropout.

CONCLUSIONS

Implications for clinical practice are discussed.

Novel approaches to treatment of generalized anxiety disorder

PURPOSE OF REVIEW

The present paper reviews recent studies on the clinical presentation of generalized anxiety disorder (GAD) and the current level of evidence for treatment with medications and psychotherapy.

RECENT FINDINGS

An apprehensive state of mind, regardless of the quality of stimuli, is at the core of GAD, causing a pervasive cognitive dysfunction that is separate from that seen in depression and obsessive compulsive disorder. When treatments reduce anxiety-related symptoms and insomnia, patients report a restoration of social functioning, probably as a consequence of improved decision-making, cooperative skills, and risk assessment. Late-onset GAD symptoms in the elderly may be caused or aggravated by cerebrovascular events, loneliness, bereavement, substance use, and the prospect of death. Insomnia in GAD may be primary or caused by common medications. Practice guidelines fail to capture the needs of the entire range of patients with GAD as they build on patients without comorbidity who have been selected for phase III trials. They are also biased to reduce cost.

SUMMARY

The past 10 years have seen a range of safe and effective treatments for GAD. Late-onset GAD presents a new challenge to researchers and practitioners. The current state of knowledge about GAD does not justify radical revisions of the diagnostic criteria in the ongoing revisions of the Diagnostic and Statistical Manual of Mental Disorders-IV and the International Statistical Classification of Diseases-10 nosologies.