RESUMEN
Several of the symptoms involved in chronic fatigue syndrome (CFS) such as fatigue, hypersomnia, hyperphagia, weight gain, and mood show seasonal variations in the general population. The aim of this study was to investigate whether patients with CFS experience seasonal fluctuations in these symptoms as well. Seasonal variation of symptoms was assessed in a group of 41 patients with CFS and 41 controls closely matched for age, gender, and city of residence. Participants were recruited across the US and were asked to complete the Seasonal Pattern Assessment Questionnaire (SPAQ) and the Profile of Mood States (POMS). CFS patients showed significantly lower scores on multiple SPAQ-derived measures as compared with controls. These included seasonal variation in energy, mood, appetite, weight, and sleep length. Patients also reported a significantly reduced sensitivity toward sunny, dry, and long days than controls. No association was noted between intensity of seasonal changes and severity of depressive symptoms. Patients with CFS exhibit an abnormally reduced seasonal variation in mood and behavior and would not be expected to benefit from light therapy.