Brett J. Deacon

Initial Severity and Antidepressant Benefits: A Meta-Analysis of Data Submitted to the Food and Drug Administration

Background Meta-analyses of antidepressant medications have reported only modest benefits over placebo treatment, and when unpublished trial data are included, the benefit falls below accepted criteria for clinical significance. Yet, the efficacy of the antidepressants may also depend on the severity of initial depression scores. The purpose of this analysis is to establish the relation of baseline severity and antidepressant efficacy using a relevant dataset of published and unpublished clinical trials. Methods and Findings We obtained data on all clinical trials submitted to the US Food and Drug Administration (FDA) for the licensing of the four new-generation antidepressants for which full datasets were available. We then used meta-analytic techniques to assess linear and quadratic effects of initial severity on improvement scores for drug and placebo groups and on drug–placebo difference scores. Drug–placebo differences increased as a function of initial severity, rising from virtually no difference at moderate levels of initial depression to a relatively small difference for patients with very severe depression, reaching conventional criteria for clinical significance only for patients at the upper end of the very severely depressed category. Meta-regression analyses indicated that the relation of baseline severity and improvement was curvilinear in drug groups and showed a strong, negative linear component in placebo groups. Conclusions Drug–placebo differences in antidepressant efficacy increase as a function of baseline severity, but are relatively small even for severely depressed patients. The relationship between initial severity and antidepressant efficacy is attributable to decreased responsiveness to placebo among very severely depressed patients, rather than to increased responsiveness to medication.

Robust Dimensions of Anxiety Sensitivity: Development and Initial Validation of the Anxiety Sensitivity Index-3.

Accumulating evidence suggests that anxiety sensitivity (fear of arousal-related sensations) plays an important role in many clinical conditions, particularly anxiety disorders. Research has increasingly focused on how the basic dimensions of anxiety sensitivity are related to various forms of psychopathology. Such work has been hampered because the original measure--the Anxiety Sensitivity Index (ASI)--was not designed to be multidimensional. Subsequently developed multidimensional measures have unstable factor structures or measure only a subset of the most widely replicated factors. Therefore, the authors developed, via factor analysis of responses from U.S. and Canadian nonclinical participants (n=2,361), an 18-item measure, the ASI-3, which assesses the 3 factors best replicated in previous research: Physical, Cognitive, and Social Concerns. Factorial validity of the ASI-3 was supported by confirmatory factor analyses of 6 replication samples, including nonclinical samples from the United States and Canada, France, Mexico, the Netherlands, and Spain (n=4,494) and a clinical sample from the United States and Canada (n=390). The ASI-3 displayed generally good performance on other indices of reliability and validity, along with evidence of improved psychometric properties over the original ASI.

Assessment of Obsessive-Compulsive Symptom Dimensions: Development and Evaluation of the Dimensional Obsessive-Compulsive Scale

Although several measures of obsessive-compulsive (OC) symptoms exist, most are limited in that they are not consistent with the most recent empirical findings on the nature and dimensional structure of obsessions and compulsions. In the present research, the authors developed and evaluated a measure called the Dimensional Obsessive-Compulsive Scale (DOCS) to address limitations of existing OC symptom measures. The DOCS is a 20-item measure that assesses the four dimensions of OC symptoms most reliably replicated in previous structural research. Factorial validity of the DOCS was supported by exploratory and confirmatory factor analyses of 3 samples, including individuals with OC disorder, those with other anxiety disorders, and nonclinical individuals. Scores on the DOCS displayed good performance on indices of reliability and validity, as well as sensitivity to treatment and diagnostic sensitivity, and hold promise as a measure of OC symptoms in clinical and research settings.

Efficacy of Cognitive Behavioral Therapy for Anxiety Disorders: A Review of Meta-Analytic Findings

Numerous clinical trials have supported the efficacy of cognitive behavioral therapy (CBT) for the treatment of anxiety disorders. Accordingly, CBT has been formally recognized as an empirically supported treatment for anxiety-related conditions. This article reviews the evidence supporting the efficacy of CBT for anxiety disorders. Specifically, contemporary meta-analytic studies on the treatment of anxiety disorders are reviewed and the efficacy of CBT is examined. Although the specific components of CBT differ depending on the study design and the anxiety disorder treated, meta-analyses suggest that CBT procedures (particularly exposure-based approaches) are highly efficacious. CBT generally outperforms wait-list and placebo controls. Thus, CBT provides incremental efficacy above and beyond nonspecific factors. For some anxiety disorders, CBT also tends to outperform other psychosocial treatment modalities. The implications of available meta-analytic findings in further delineating the efficacy and dissemination of CBT for anxiety disorders are discussed.

The relevance of analogue studies for understanding obsessions and compulsions

Analogue samples are often used to study obsessive-compulsive (OC) symptoms and related phenomena. This approach is based on the hypothesis that results derived from such samples are relevant to understanding OC symptoms in individuals with a diagnosis of obsessive-compulsive disorder (OCD). Two decades ago, Gibbs (1996) reviewed the available literature and found initial support for this hypothesis. Since then there have been many important advances addressing this issue. The purpose of the present review was to synthesize various lines of research examining the assumptions of using analogue samples to draw inferences about people with OCD. We reviewed research on the prevalence of OC symptoms in non-clinical populations, the dimensional (vs. categorical) nature of these symptoms, phenomenology, etiology, and studies on developmental and maintenance factors in clinical and analogue samples. We also considered the relevance of analogue samples in OCD treatment research. The available evidence suggests research with analogue samples is highly relevant for understanding OC symptoms. Guidelines for the appropriate use of analogue designs and samples are suggested.

The biomedical model of mental disorder: a critical analysis of its validity, utility, and effects on psychotherapy research.

The biomedical model posits that mental disorders are brain diseases and emphasizes pharmacological treatment to target presumed biological abnormalities. A biologically-focused approach to science, policy, and practice has dominated the American healthcare system for more than three decades. During this time, the use of psychiatric medications has sharply increased and mental disorders have become commonly regarded as brain diseases caused by chemical imbalances that are corrected with disease-specific drugs. However, despite widespread faith in the potential of neuroscience to revolutionize mental health practice, the biomedical model era has been characterized by a broad lack of clinical innovation and poor mental health outcomes. In addition, the biomedical paradigm has profoundly affected clinical psychology via the adoption of drug trial methodology in psychotherapy research. Although this approach has spurred the development of empirically supported psychological treatments for numerous mental disorders, it has neglected treatment process, inhibited treatment innovation and dissemination, and divided the field along scientist and practitioner lines. The neglected biopsychosocial model represents an appealing alternative to the biomedical approach, and an honest and public dialog about the validity and utility of the biomedical paradigm is urgently needed.

A magnetic resonance spectroscopy investigation of obsessive–compulsive disorder and anxiety

The aim of the current study was to use proton magnetic resonance spectroscopy (MRS) to investigate potential irregularities in neurochemical compounds in obsessive-compulsive disorder (OCD) and the extent to which these irregularities are related to state anxiety. Single voxel MRS was used to image the head of the caudate nucleus (HOC) and orbitofrontal white matter (OFWM) bilaterally in adult patients with OCD and a control group. The results indicated that patients with OCD had increased levels of a combined measure of glutamate and glutamine (Glx/Cr) and N-acetyl-l-aspartic acid (NAA/Cr) relative to creatine in the right OFWM and reduced levels of myo-inositol relative to creatine (mI/Cr) in the HOC bilaterally. Correlational analyses indicated that Glx/Cr in the OFWM was related to OCD symptoms, while mI/Cr in the HOC was related to trait and/or state anxiety. Reanalysis of the significant group differences controlling for state anxiety symptoms erased three of the four group differences. These results are discussed in context of the methodological difficulties facing this area of research.

The Short Health Anxiety Inventory: Psychometric Properties and Construct Validity in a Non-clinical Sample

Contemporary conceptualizations of hypochondriasis (HC) as severe health anxiety have led to the development of cognitive-behavioral approaches to understanding, assessing, and treating this problem. The Short Health Anxiety Inventory (SHAI) is a new instrument that measures cognitive factors associated with HC. In the present study, we examined the psychometric properties and factor structure of the SHAI in a large sample of medically healthy university students. We also examined the scale’s convergent, divergent, and predictive validity. Results indicated that the SHAI has good psychometric properties and contains three factors that assess the perceived likelihood and perceived severity of becoming ill, and body vigilance. Facets of health anxiety uniquely predicted increased safety-seeking behavior and medical utilization, behaviors that are commonly observed in HC. Results are discussed in terms of the cognitive-behavioral model of HC.

Is hypochondriasis an anxiety disorder

Although hypochondriasis is currently classified as a somatoform disorder, the underlying cognitive processes may be more consistent with an anxiety disorder. This observation has important implications for treatment and subsequent revisions of the diagnostic classification of hypochondriasis.

Is hypochondriasis related to obsessive-compulsive disorder, panic disorder, or both? An empirical evaluation

Although hypochondriasis (HC) is considered a somatoform disorder in the Diagnostic and Statistical Manual of Mental Disorders (4th ed., text revision), some authors have pointed out that the symptoms of HC overlap with certain anxiety disorders, namely, panic disorder (PD) and obsessive-compulsive disorder (OCD). Few studies have empirically addressed this overlap. In the present investigation, we used discriminant function analysis to explore how patients with a principal diagnosis of HC, OCD, or PD varied with respect to cardinal symptoms of these disorders (i.e., health anxiety, obsessions and compulsions, and panic-related anxiety and avoidance) and key cognitive biases (i.e., intolerance of uncertainty, anxiety sensitivity, and body vigilance). Fifty treatment-seeking individuals with PD, 21 with OCD, and 23 with HC completed self-report measures of symptoms and cognitions during their clinic visit. Results indicated that whereas individuals with HC experience panic attacks, obsessions, and compulsions, these symptoms are markedly less pronounced than among those with PD and OCD. Conversely, overlaps were found in terms of cognitive biases, with HC patients demonstrating elevated levels of intolerance of uncertainty, body vigilance, and fear of cardiovascular symptoms. Implications for the conceptualization and treatment of HC are discussed.