Do adolescents with chronic fatigue syndrome (CFS/ME) and co-morbid anxiety and/or depressive symptoms think differently to those who do not have co-morbid psychopathology?

Background: Co-morbid anxiety and/or depression is common in adolescents with Chronic Fatigue Syndrome (CFS/ME). Adolescents with psychopathology typically endorse more negative cognitive errors. We do not know whether they make negative cognitive errors in response to fatigue. We examined the thinking patterns of adolescents with CFS/ME and co-morbid psychopathology compared to those without this co-morbidity.

Methods: This cross-sectional study recruited 205 adolescents (age 11-18) with CFS/ME, who completed measures of anxiety and depression, information processing biases and responses to fatigue. We grouped participants as having co-morbid psychopathology (or not) by applying a threshold score. We compared groups' thinking pattern subscale scores using independent samples T tests. We examined the association between psychopathology and general negative thinking and specific responses to fatigue symptoms.

Results: Adolescents with CFS/ME with co-morbid psychopathology more strongly endorsed general negative cognitive errors (d = 0.61-1.31). They also more strongly endorsed damage beliefs (d = 0.49), embarrassment avoidance (d = 1.05), catastrophising (d = 0.97) and symptom focusing (d = 0.75) in response to fatigue but did not differ significantly on fear avoidance from those without co-morbid psychopathology. Both negative cognitive errors and unhelpful responses to symptoms explained 43% of the variance in psychopathology.

Conclusions: Adolescents with CFS/ME with co-morbid psychopathology tend to be negatively biased in their thinking, both generally and about their symptoms of fatigue specifically. This may have implications for the sequencing of cognitive and behavioural strategies to address both fatigue and psychopathology.