The NCS-R survey conducted from February 2001 to April 2003 implemented several methodological innovations, according to Kessler. It used the international World Health Organization Composite International Diagnostic Interview (WHO-CIDI), a fully structured, lay-administered interview, to generate DSM-IV diagnoses, but then added in-depth clinical validation of field research diagnoses based on the clinician-administered Structured Clinical Interview for DSM-IV (SCID) reinterviews, dimensional self-ratings on clinical anchored scales, inclusion of subthreshold diagnostic syndromes, assessment of severity, assessments of service use and evaluations of treatment adequacy along with an expanded set of diagnoses.
Kessler said he grouped ADHD, IED, CD and ODD as impulse control disorders, because he thought that the most defining characteristic that they shared was the impulsivity. He noted that these disorders have not been well studied in adults, particularly IED.
"We have an enormous number of articles about panic attacks ... but you can count on one hand all the things that have been done about anger attacks," he said.
The lack of research on IED is mystifying to Kessler, because "when you look at the data, you find it is roughly as prevalent as panic disorder [12-month prevalence is 2.6% for IED and 2.7% for panic disorder], it certainly has an impact on people's lives as much as panic disorder, and it certainly has more impact on the lives of loved ones than panic disorder."
He acknowledged that many are confused as to whether IED should be classified as an illness and whose job it is to take care of the people who suffer from it.
"It is clearly not something that is seen as being in the core of psychiatry," he said. "But anger attacks are, in fact, very common in the population. And we find that both people with anger attacks and those with panic attacks have a strong family history of mood disorder. The anger attacks have an earlier age of onset and are more fundamental in being involved in high comorbidity," Kessler said.
Also, there is an interesting mating correlation, he added. Women with panic attacks are often married to men who have anger attacks.
With regard to the inclusion of ADHD under the impulse control category, Kessler said, "There is a lot of evidence suggesting ADHD does continue into adulthood. It is not the same thing as being aggressive, but we were looking at the fingers that radiate out from that interest in aggressiveness."