Mood volatility with rumination but neither attentional nor interpretation biases in chronic fatigue syndrome.

OBJECTIVES: This study tested whether (1) chronic fatigue syndrome (CFS) individuals have a bias in the initial orientation of attention to illness-related information, which is enhanced by rumination. (2) CFS individuals have an illness interpretation bias (IB) in their early automatic processing of ambiguous information. (3) CFS individuals experience a greater degree of mood fluctuation following rumination and distraction inductions. DESIGN: Thirty-three CFS participants who had received a medical practitioner's diagnosis of CFS were compared to 33 healthy matched controls on an exogenous cueing task and a lexical decision task. METHOD: All participants underwent either a rumination or distraction induction. They then completed an exogenous cueing task to assess bias to illness and social threat compared with neutral stimuli, as well as a lexical decision task to assess their interpretation of ambiguous words having illness, social threat, or neutral interpretations. RESULTS: Reaction time data revealed that CFS individuals did not have an attentional bias (AB) in the initial orientation of attention to illness-related material. Nor was there an IB towards illness in CFS individual's automatic response to ambiguous information. However, as hypothesized, CFS individuals showed a greater degree of mood fluctuation following the rumination/distraction induction. CONCLUSION: Rumination and distraction lead to greater mood volatility in CFS individuals than in controls, but not to attentional nor interpretation biases in the early automatic stages of information processing in CFS individuals.