Adolescent's descriptions of fatigue, fluctuation and payback in chronic fatigue syndrome/myalgic encephalopathy (CFS/ME): interviews with adolescents and parents.

Observed Findings

• All 21 adolescents reported fatigue as a core symptom, with natural fluctuation including good days and bad days.
• All adolescents reported payback (increased symptoms) following activity, but the threshold of activity required to trigger payback varied among participants.
• Adolescents differed in how they described fatigue (as a single symptom versus a collection of multiple symptoms) and symptom constancy (constant versus variable).
• Functional impact ranged from limiting leisure activities, to struggling with daily self-care, to predominantly sedentary lifestyle.
• The majority of participants were female (16 of 21) and aged 12–17 years (mean 14.4), recruited from a single specialist paediatric service.

Inferred Conclusions

• Fatigue, symptom fluctuation, and post-exertional payback are core, universal features of adolescent CFS/ME.
• Significant heterogeneity exists in how adolescents experience and describe their symptoms and the degree to which symptoms impact daily functioning.
• Individual patient assessment and outcome measures must account for this heterogeneity rather than assuming uniform symptom presentation.
• Further research is needed to understand the basis for this variability and to develop more personalized outcome measures for this population.

Remaining Questions