Test effort in persons with Chronic Fatigue Syndrome when assessed using the Validity Indicator Profile

The current study examined the potential contribution of suboptimal effort to the cognitive deficits that are associated with Chronic Fatigue Syndrome (CFS) using the Validity Indicator Profile (VIP). Unlike most tests of effort, the VIP distinguishes between intentional and unintentional poor performance and does not assess cognitive functions that are affected by CFS, thereby reducing the risk of mistakenly attributing genuinely poor performance to reduced effort. The VIP was administered to 54 persons with CFS and 54 matched healthy community controls, and performance categorized into 1 of 4 response styles (valid: compliant; invalid: suppressed, irrelevant, inconsistent), based on the level of effort expended (high or low) and the intention to perform well or not. VIP performance was classified as valid for the majority of participants (CFS and controls), indicating high levels of effort and an intention to perform well. Three participants in the CFS group and four in the control group showed low levels of effort but an intention to do well (invalid: inconsistent). No participant performed in a manner indicative of an intent to perform poorly (invalid: suppressed, inconsistent). These findings suggest that poor effort is unlikely to contribute to cognitive test performance of persons with CFS.

Functional status, neuropsychological functioning, and mood in chronic fatigue syndrome (CFS): relationship to psychiatric disorder

Individuals with chronic fatigue syndrome (CFS) face chronic physical debilitation, reduced neuropsychological functioning, and changes in emotional well-being that significantly detract from quality of life. The role of psychiatric disturbance in reducing quality of life in CFS remains unclear. In the current investigation, the role of psychiatric status in reducing health-related quality of life in CFS was examined. Four subject groups were compared on measures of functional well-being, mood, and neuropsychological status: individuals with CFS and no history of psychiatric illness, individuals who had current symptoms of psychiatric illness that began after their CFS diagnosis, individuals who had current symptoms of psychiatric illness that began before their CFS diagnosis, and a healthy sedentary control group. Overall, it was found that individuals with CFS suffer from profound physical impairment. Concurrent psychiatric illness, however, did not adversely affect physical functional capacity. Physical functional capacity was not worse in individuals with a concurrent psychiatric illness. As expected, concurrent psychiatric illness was found to reduce emotional well-being. Moreover, individuals with a psychiatric illness that predated the onset of CFS suffered the greatest emotional distress. Thus, an individual's psychiatric history should be considered when attempting to understand the factors maintaining disability in CFS.