TUCSON - Generalized anxiety disorder, already the most common of the anxiety disorders, could double in prevalence in clinical practice with adoption of changes now under consideration for the coming edition of psychiatry’s diagnostic and statistical manual, the DSM-5.
The DSM-5 Anxiety, Obsessive-Compulsive Spectrum, Posttraumatic, and Dissociative Disorders Work Group is planning to give generalized anxiety disorder (GAD) a major overhaul. The makeover could very well begin with its name, which might be changed to Generalized Worry Disorder in recognition that excessive worry is the disorder’s cardinal feature.
Dr. Alan J. Gelenberg
But it’s the DSM-5 working group’s current weighing of a shortening in the duration criterion that would result in a potentially dramatic increase in the number of individuals meeting the diagnostic standard for GAD. Since the introduction of DSM-IV in 1994, the diagnosis of GAD has required excessive anxiety and worry for a minimum of 6 months, up from at least 1 month in the 1980 DSM-III, where GAD first burst on the scene as a formal new diagnostic entity.
"GAD was a residual diagnosis – a wastebasket diagnosis – in DSM-III. The duration criterion was somewhat arbitrarily elevated to 6 months in DSM-IV. That 6-month requirement is now very much in play," Dr. Alan J. Gelenberg said at the annual psychopharmacology review sponsored by the University of Arizona.
"I think what we will see in DSM-5 is that the duration criterion will probably go back to 1 month," predicted Dr. Gelenberg, an authority on GAD who is professor and chair of the department of psychiatry at Pennsylvania State University, Hershey.
A study by Dr. Jules Angst and his colleagues at Zurich University Psychiatric Hospital concluded that the 6-month duration criterion for GAD could not be confirmed as clinically meaningful. Based upon data from the prospective Zurich Cohort Study, the investigators found no significant differences in terms of distress, work impairment, family history of anxiety, or comorbid major depression, bipolar disorder, or suicide attempts in groups of patients diagnosed with GAD based upon symptom durations of 2 weeks, 1 month, 3 months, and 6 months. Moreover, twice as many patients were identified as having GAD based upon a 1-month criterion compared with the current 6-month requirement (Psychol. Med. 2006;36:1283-92).
Similarly, Australian investigators reviewing the likely impact of proposed options for the DSM-5 diagnosis of GAD concluded that the 1-year prevalence of the anxiety disorder Down Under would jump from 1.7% using the DSM-IV definition to 3.2% with a 1-month duration criterion (Depress. Anxiety 2010;27:134-47).
The DSM-V GAD work group has stirred up considerable controversy. Other changes under consideration include deleting sleep disturbances and irritability from the list of associated symptoms on the grounds that they are insufficiently specific. The work group also is weighing reintroduction of dimensional attributes such as anxiety and depression to serve as adjuncts to the current categorical attributes.
"If there’s any psychiatric diagnosis where a dimension is relevant, it’s GAD, where some social animals – and not only humans – are just born with a greater propensity to manifest anxiety in response to normal stimuli," the psychiatrist observed.
Comorbidity is the rule in GAD. The lifetime prevalence of psychiatric comorbidity in patients with GAD is greater than 90%. At some point, 62% of individuals with GAD will qualify for a diagnosis of major depression, 38% for alcohol abuse or dependence, and 24% for panic disorder.
The incidence of major depressive disorder rises over time in patients with GAD. However, depression precedes GAD chronologically as often as vice versa. A question that remains very much alive in the psychiatric literature, according to Dr. Gelenberg, is whether GAD and major depressive disorder are a single entity or separate but related diagnostic categories. Circumstantial evidence supportive of the single-disorder hypothesis includes evidence of shared genetic risk, the 2:1 female preponderance common to both GAD and major depression, and shared childhood risk factors, including physical, sexual, and verbal abuse, and parental divorce. Plus, he noted, the effective treatments are similar.
Ample evidence exists dating back as far as the 1990s that GAD causes as much impairment as major depression. Indeed, GAD adversely affects quality of life even more than schizophrenia or bipolar disorder. Patients with GAD are high users of health care, but they are far more likely to seek help from a primary care physician than from a psychiatrist. Indeed, one classic study showed that twice as many patients with GAD were in treatment with gastroenterologists – typically having been diagnosed with irritable bowel syndrome – as were under psychiatric care.