The Infrequency of "Pure Culture" Diagnoses Among the Anxiety Disorders
Anxiety disorders are known to commonly coexist in individuals, both with other anxiety disorders and with mental disorders from other groupings, such as affective disorders. We questioned how frequently anxiety disorders actually occur in isolation, as "pure cultures."
We examined diagnostic patterns among the 711 subjects entered into a large, multicenter study of anxiety disorders, the Harvard/ Brown Anxiety Disorders Research Program (HARP), which focused on panic, agoraphobia, generalized anxiety disorder, and social phobias as "index disorders" required for intake.
We used various definitions for "pure culture." By all definitions, subjects with "pure culture" represented a minority, especially in cases of generalized anxiety disorder and social phobia, where comorbidity was virtually ubiquitous. "Pure culture" status was associated with later onset of illness and less chronicity.
Future studies of anxiety disorder should aim to document the extensive comorbidity, rather than eliminate it by restrictive diagnostic exclusion criteria, lest they yield atypical or even misrepresented groups of patients. Clinicians should not stop at identifying only the "main" diagnosis but look for other, comorbid diagnoses that are often present.
Available from: Claude Belanger
- "These two anxiety disorders have high rates of comorbidity. For instance, in the Harvard/Brown Anxiety Disorders Research Program, a 55% to 88% comorbidity rate was found for people with a primary diagnosis of PDA, and 83% to 94% comorbidity rate was found for people with a primary diagnosis of GAD (Goldenberg et al., 1996; Wittchen et al., 2004). Moreover, the Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; DSM-IV-TR; American Psychiatric Association [APA], 2000) reports a PDA/ GAD 1 comorbidity rate of 25%. "
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ABSTRACT: Concurrent panic disorder with agoraphobia (PDA) and generalized anxiety disorder (GAD) are the most common diagnostic occurrences among anxiety disorders. This particular comorbidity is associated with significant impairments in quality of life (QOL). The current study sought to investigate the efficacy of a combined cognitive-behavioral psychotherapy that addressed both conditions compared with a conventional psychotherapy, which attends solely to the primary disorder. The hypotheses postulated firstly, that both treatment conditions would lead to improvements in participants' QOL and secondly, that the combined therapy would lead to greater QOL ameliorations. Twenty-five participants with comorbid PDA/GAD diagnoses were evaluated with a number of clinical interviews and self-report questionnaires, and were provided with either conventional or combined cognitive-behavioral psychotherapy, which consisted of 14 one-hour weekly sessions. Participants were once again evaluated in the same fashion 2-weeks after the completion of the psychotherapy. The results revealed that both conditions led to significant improvements in participants' QOL, but that the two groups did not significantly differ in terms of the effect on QOL. The results also reveal that the two conditions did not significantly differ in terms of their effect on PDA and GAD symptomatology or psychiatric comorbidity. The results demonstrate that the combined psychotherapy, which addresses both conditions simultaneously, is similar to the conventional psychotherapy employed for the primary disorder in terms of QOL enhancement, symptom severity, and comorbidity reduction.
Available from: Nicolas Hoertel
- "While some of the criteria have been implemented for safety reasons (e.g., pregnancy, significant medical conditiony), some others exclude a significant proportion of the population likely to seek care in clinical setting (e.g., current depression, lifetime history of bipolar disorder, recent history of substance use disorder). The exclusion of participants currently presenting with a drug or alcohol use disorder or a depression may be particularly significant, since these comorbidities are highly prevalent in patients with PD (Goldenberg et al., 1996). Thus, whether the results of clinical trials may apply in community setting is poorly known. "
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Research on the generalizability of clinical trials in panic disorder is limited. The present study sought to quantify the generalizability of clinical trials' results of individuals with DSM-IV panic disorder (PD) to a large community sample.
Data were derived from the National Epidemiological Survey on Alcohol and Related Conditions (NESARC), a large national representative sample of 43,093 adults of the United States population. We applied a standard set of eligibility criteria representative of PD clinical trials to all adults with past 12 months PD (n=907), and then to a subgroup of participants seeking treatment (n=105). Our aim was to determine the proportion of participants with PD who would have been excluded by typical eligibility criteria.
We found that more than 8 out of ten participants (80.52%; 95% CI=77.13-83.52%) with PD were excluded by at least one criterion. In the subgroup of participants who sought treatment, the exclusion rate by at least one criterion was higher (92.40%; 95% CI=84.60-96.42%). For the full sample and the treatment-seeking subsample, having currently a depression and a diagnosis of alcohol or drug abuse/dependence were the criteria excluding the highest percentage of participants. Having a lifetime history of bipolar disorder and a current significant medical condition also excluded a substantial proportion of individuals in both samples. Exclusion rates were similar when considering panic disorder with and without agoraphobia.
Clinical trials, that exclude a majority of adults with panic disorder, should carefully consider the impact of eligibility criteria on the generalizability of their results. As required by CONSORT guidelines, reporting exclusion rate estimate and reasons of eligibility should be mandatory in both clinical trials and meta-analyses.
Available from: research.brown.edu
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