Vol.2, No.2, 90-96 (2010) doi: 10.4236/health.2010.22015 SciRes Copyright 2010 Openly accessible at http://www.scirp.org/journal/health/ http://tinyurl.com/yh8b6u4 (my bolds and spacing. Sorry - it was too long to post in the library) Subgroups of chronic fatigue syndrome based on psychiatric disorder onset and current psychiatric status Molly M. Brown, Carly Kaplan, Leonard A. Jason, Christopher B. Keys Center for Community Research, DePaul University, Chicago, USA; firstname.lastname@example.org Received 22 October 2009; revised 2 December 2009; accepted 4 December 2009. ABSTRACT Few studies have examined the effects of psy-chiatric disorders occurring over a long duration among patients with chronic fatigue syn-drome (CFS). The role of premorbid and current psychiatric disorders in impairment was explored with a sample of 113 participants with CFS. Subgroups were created based on past and current psychiatric status including those whose psychiatric history was premorbid and current, postmorbid and current, past but not current, and those with no lifetime diagnosis. Results from a one-way MANOVA revealed that patients with a premorbid and current psychiatric disorder reported significantly higher pain severity, more somatic symptoms, poorer sleep quality, and poorer quality of life than those with no psychiatric history. Levels of fatigue and physical functioning among patients with CFS were unrelated to the four subgroups in this study. Although those with a premorbid and current psychiatric disorder were differentiated from those with no psychiatric history on some markers of impairment, the sample as a whole had severe fatigue-related impairment, which is the cardinal symptom of CFS. Implications for research are discussed. Keywords: Chronic Fatigue Syndrome; Psychiatric Comorbidity; Subgroups; Impairment 1. INTRODUCTION Chronic fatigue syndrome (CFS) is a chronic, debilitating illness that remains poorly understood. Some patients with CFS experience psychiatric symptoms, but the role of these symptoms in the development, maintenance, and severity of the illness is unclear. Several studies have found high rates of psychiatric comorbidity among patients with CFS in the range of 45% to 50%, [1, 2] and up to 82% for a lifetime psychiatric diagnosis,  exceeding rates in the general population. A number of studies have examined the role of co-morbid psychiatric issues in the course of CFS. While one study found that patients with CFS who had a co-morbid psychiatric diagnosis had significantly more severe fatigue than those without a psychiatric disorder,  most research has not found that psychiatric comorbidity increases impairment in CFS. Studies comparing patients with and without psychiatric comorbidity have found no differences in impairment in sleep,  neuro-cognitive functioning, [6,8] physical functioning, [9,11] fatigue severity,  and widespread pain.  These results suggest that psychiatric comorbidity is not related to higher illness severity in this population. Due to the unexpected lack of evidence for a relationship between psychiatric comorbidity and illness seve-ity in CFS, it is perhaps more important to explore long-term psychiatric status in CFS, as opposed to present psychiatric comorbidity only. Individuals with psychiatric illness early in life may be more likely to develop CFS later in life,  indicating that a subgroup of patients with CFS may have a long-term history of psychiatric disorder beginning prior to the onset of CFS. It has been hypothesized that an onset of psychiatric disorder predating CFS may be indicative of a long history of poor coping skills, leading to increased impairment. . Tiersky, Matheis, DeLuca, Lange, and Natelson  developed psychiatric subgroups based upon whether the onset of the psychiatric disorder was before (premorbid) or after (postmorbid) CFS onset. They found that patients with CFS with a premorbid nd current psychiatric diagnosis performed significantly worse on neuropsy-chological tests than patients with no history of psychiatric disorder and healthy controls. However, they did not find increased physical impairment in this subgroup. Tiersky et al. developed more specific psychiatric sub-groups of patients with CFS compared to previous studies. Nonetheless, their study did not include patients who had a psychiatric disorder in the past but did not currently meet criteria for the disorder. In other words, it may also be important to examine CFS severity for people who have recovered from a past psychiatric disorder, as remission from a psychiatric illness is associated with increased self-efficacy  and may be indicative of adaptive coping leading to better functioning. Further, the authors did not explore some key features of CFS severity such as sleep quality, pain severity, and diversity of symptoms. The present study examined four groups of patients with CFS: those with a premorbid and current psychiat-ric diagnosis, those with a postmorbid and current psy-chiatric diagnosis, those with a past (either premorbid or postmorbid) but no current psychiatric diagnosis, and those with no history of psychiatric diagnosis. We hypothesized that patients with a premorbid and current psychiatric disorder would have increased physical and psychiatric impairment compared to patients with a postmorbid and current psychiatric diagnosis, those with a past but not current psychiatric disorder, and those with no history of psychiatric disorder. ........................................ 2. METHODS <snip> see full text ---------------------------------------- 3. RESULTS 3.1. Demographic Characteristics In regards to demographic characteristics, 83.2% of par-ticipants were female. The average age was 43.8 years. Regarding ethnicity, 87.6% were White, 4.4% were Af-rican American, 4.4% were Latino, and 3.5% were Asian American. As for marital status, 48.7% were married or living with a partner, 32.7% were single, and 17.7% were divorced or separated. In terms of work status, 40.7% were working or full time students and 59.3% were part-time students, retired, unemployed or on dis-ability. With regards to education, 46.9% had earned a standard college degree, 22.1% had a graduate or pro-fessional degree, 21.2% had partial college, and 9.7% had a high school/GED degree or less. No significant differences were found among the four groups in terms of demographic variables. Table 1. Lifetime Psychiatric Diagnoses for Psychiatric Subgroups. Premorbid and current (n = 32) Postmorbid and current (n = 12) Past but not current (n = 28) Sig. Any Mood Disorder 59.4% 58.3% 50.0% Major Depressive Disorder 50.0% 58.3% 46.4% Dysthymic Disorder 18.8% 0.0% 0.0% * Other Mood Disorder 0.0% 0.0% 3.6% Any Anxiety Disorder 56.3% 33.3% 46.4% Generalized Anxiety Disorder 9.4% 8.3% 3.6% Panic Disorder (with or without Agoraphobia) 25.0% 16.7% 17.9% Posttraumatic Stress Disorder 37.5% 0.0% 10.7% ** Other Anxiety Disorder 6.3% 8.3% 10.7% Adjustment Disorder 21.9% 33.3% 7.1% Other 25.0% 0.0% 14.3% Total Lifetime Psychiatric Disorders (Mean) 1.97 a, b 1.25 a 1.25 b *** Notes: *p < .05, **p < .01, ***p < .001; Similar letters across rows indicate significant difference 3.2. Diagnostic Outcomes Total lifetime psychiatric diagnoses and rates of different psychiatric diagnostic categories were compared for the three groups with a history of psychiatric disorder (Ta-ble 1). Fisher’s Exact Tests revealed that the three groups did not differ in terms of lifetime presence of anxiety or mood disorders. When comparing differences among the three psychiatric groups for specific psychiatric diagno-ses, a significant difference was revealed for lifetime dysthymic disorder (p = .02), and the premorbid and current psychiatric group had the highest rate (18.8%) compared to the other two groups with rates of 0%. A significant difference between groups was also found for lifetime posttraumatic stress disorder (p = .01). The premorbid and current group had the highest rate of posttraumatic stress disorder (37.5%), the past but not current group had the second highest rate (10.7%), and no participants from the postmorbid and current group met criteria during their lifetime. A one-way ANOVA revealed that the groups signifi-cantly differed on total number of lifetime psychiatric diagnoses, F(2, 69) = 9.19, p < .001. Bonferroni post hoc analyses indicated that the premorbid and current psy-chiatric group had significantly more lifetime psychiatric diagnoses than both the postmorbid and current group (p = .01), and the past but not current group (p = .003). 3.3. Main Outcomes Sixteen participants had missing data for one or more of the self-report outcome measures and were therefore excluded, which left a total of 97 participants for analy-sis of main outcomes (See Table 2). Results from the one-way MANOVA revealed a significant overall mul-tivariate effect for psychiatric group on the combined DVs, Wilks’ Lambda = .68, p = .03. Descriptive statistics for outcomes are reported in Ta-ble 2. Upon examination of univariate effects, signifi-cant differences were found for pain severity [F(3, 93) = 3.08, p = .03], pain interference [F(3, 93) = 3.27, p = .03], total somatic symptoms [F(3, 93) = 3.86, p = .01], sleep quality [F(3, 93) = 4.59, p = .01], and quality of life [F(3, 93) = 3.31, p = .02]. No significant univariate effects were found for fatigue severity or physical func-tioning. Bonferroni post hoc tests revealed the premorbid and current group scored significantly worse than the no lifetime diagnosis group for pain severity (p = .02), pain interference (p = .02), total somatic symptoms (p = .03), sleep quality (p = .003), and quality of life (p = .02). 4. DISCUSSIONS Patients with CFS with a premorbid and current psychi-atric disorder reported significantly higher pain severity and interference, more somatic symptoms, poorer sleep quality, and poorer quality of life than those who have never been diagnosed with a psychiatric disorder. No ignificant differences in impairment were found for participants in the other two psychiatric history groups compared to the no lifetime diagnosis group. These re-sults in combination with two of Tiersky et al.’s  neuropsychological findings suggest that patients with CFS who have a premorbid and current psychiatric dis-order have significantly more impairment than those with no psychiatric history, while patients with other categorizations of psychiatric history are not differenti-ated from patients without a psychiatric history in terms of impairment. However, the postmorbid and current psychiatric group did, in fact, demonstrate the highest level of fatigue severity and the most somatic symptoms compared to the other three groups, but significant dif-ferences were not revealed due to the small sample size for this group. Although patients with a premorbid and current psychiatric history were found to represent a subset of the CFS population that experiences particu-larly severe illness symptomatology, patients with a postmorbid and current diagnosis may also have in-creased illness severity. Despite findings of increased impairment on some outcomes for those who had premorbid and current psy-chiatric diagnoses, no differences were found between groups for physical functioning or fatigue severity. Moreover, it is evident from this study that patients with and without psychiatric disorders exhibit notably high levels of fatigue and disability. These findings are con-sistent with previous research demonstrating that psy-chiatric comorbidity does not differentiate patients in terms of physical functioning  or fatigue severity.  Of note is that fatigue is the cardinal symptom of CFS, and findings from this and previous studies suggest that this symptom is present at a severe level regardless of psychiatric status. In terms of severity of psychiatric functioning among patients with CFS, our prediction that the premorbid and current psychiatric group would evidence the most psy-chiatric dysfunction as defined by more lifetime psychi-atric diagnoses was confirmed and was consistent with prior research.  This finding suggests that patients who have had ongoing mental health issues beginning prior to CFS onset tend to have more pervasive emo-tional problems. High levels of psychiatric impairment over time, in turn, may be related to increased ill-ness-related impairment compared to those with a shorter-term history of psychiatric disorder. The premorbid and current group had, on average, a total of 16.21 somatic symptoms compared to the no history group which had an average of 13.37 symptoms. This greater number of somatic symptoms suggests that the clinical presentation of patients with longstanding mental health issues is more complex than those without a psychiatric history. Exclusion of premorbid psychiatric disorder in CFS samples has been used to reduce sample heterogeneity in some studies.  Results from this study provide support for sample selection strategies that take into consideration premorbid psychiatric function-ing, as long-term psychiatric status adds complexity to the illness symptomatology. Several limitations can be noted for the present inves-tigation. The use of self-reported onsets of psychiatric disorder and CFS to determine psychiatric subgroups may be problematic, as both are vulnerable to recall bias. [35,36] Further, research has shown that those with a gradual CFS onset were more likely to report long-term depressive symptomatology gradually leading to the on- set of the illness.  Thus, the self-reported onset of CFS in the present study may not have been accurate for all participants, particularly those who also had a gradual illness onset. Finally, differences between groups may not have been revealed in the analysis due to small sam-ple sizes and low power. Future research with a larger sample size is needed to more fully explore functioning among patients with a postmorbid and current psychiat-ric diagnosis. This study added to previous research demonstrating that neuropsychological functioning is impacted based on premorbid and current psychiatric status.  The findings indicated that long term psychiatric dysfunction increased impairment on several key indicators of CFS severity: sleep difficulties, pain, and wide ranging so-matic symptoms. However, the sample as a whole had high levels of fatigue and physical impairment which were unrelated to the four subtypes, suggesting that even patients without a psychiatric history suffer from severe disability. 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