Journal of IiME Volume 1 Issue 1 Professor Leonard Jason Exploratory Subgrouping in CFS: Infectious, Inflammatory, and Other Karina M. Corradi, Leonard A. Jason,∗ Torres-Harding Introduction Professor Leonard Jason Professor of Clin. & Community Psychology, Director, Center for Community Research, DePaul University, Chicago Dr. Leonard Jason, Ph.D., is among the most prolific of all CFIDS researchers. more than a decade, Dr. Jason and his team at DePaul University’s Centre for Community Research have worked to define the scope and impact of CFS/ME worldwide. Professor Jason was intending to speak at our London conference but was forced to cancel due to other engagements. Similar to other disorders such as cancer, it is likely that a number of distinct types of CFS exist, and that grouping all individuals who meet diagnostic criteria together is prohibiting the identification of these distinct biological markers of the individual subgroups Chronic fatigue syndrome (CFS) affects an estimated 836,000 adults in the United States (Jason et al., 1999), and is 3 to 5 times more common in women than men. CFS can impact any number of bodily systems including For neurological, immunological, hormonal, gastrointestinal, and musculoskeletal (Friedberg & Jason, 1998). CFS is a diagnosis of exclusion. There are currently no specific diagnostic tests for its identification. Researchers have reported various biological abnormalities when investigating CFS, including hormonal abnormalities (Cannon et al., 1998; Moorkens, Berwaerts, Wynants & Abs, 2000), immune activation (Miller, Cohen & Ritchey, 2002), neuroendocrine changes, (Farrar, Locke & Kantrowitz, 1995) and neurological abnormalities (Cook, Lange, DeLuca & Natelson, 2001) among others. However, studies involving basic blood work appear to show no typical pattern of abnormality among individuals with CFS (Johnson, DeLuca & Natelson, 1999). It has been suggested that a number of unique subgroups exist within the overall cluster of individuals diagnosed with this disorder (Cukor, Tiersky & Natelson, 2000; Jason et al. 2001; Johnson, DeLuca & Natelson, 1999). In the p aper specifying the current US case definition for CFS diagnosis (Fukuda et al., 1 994), the working group that developed the criteria referred to the importance of subgrouping within cohorts of individuals diagnosed with CFS. This demonstrates that, even as the current definitional criteria were being presented, there was an awareness of the heterogeneity within the identified group. After the publication of these criteria in 1994, many attempts to subgroup have been undertaken, but to date, no one method has proven to be consistently superior in differentiating subgroups. Psychiatric comorbidity has often been considered a differentiating variable in research studies aimed at subgrouping (Borish et al., 1998; Cukor, Tiersky and Natelson, 2000; DeLuca, Johnson, Ellis & Natelson, 1997a; Masuda, Munemoto, Yamanaka, Takei & Tei, 2002). However, when Tiersky, Matheis, DeLuca, Lange, and Natelson (2003) examined individuals with CFS with and without psychiatric co-morbidity, they found that physical functional capacity was not worse in individuals with CFS and a concurrent psychiatric illness. Morriss and associates (1999) also found that depression was not associated with the reporting of pain, FM, with CFS. Similarly, Ciccone, Busichio, Vickroy, and Natelson (2003) did not find that psychiatric illness, alone or in combination with a comorbid personality disorder, was associated with physical impairment. (continued page 9) Susan R. Keywords: chronic fatigue syndrome, subgrouping, physical disability, mental disability, psychiatric comorbidity 8 IBS, or medically unexplained symptoms in individuals Invest in ME Charity Nr 1114035 www.investinme.org
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