E3 PreliminaryPreliminaryPEM not requiredCase-ControlPeer-reviewedMachine draft
Standard · 3 min
Valacyclovir treatment of chronic fatigue in adolescents.
Henderson, Theodore A · Advances in mind-body medicine · 2014
Quick Summary
This study looked at 15 young people who were referred for treatment-resistant depression but were found to have ME/CFS instead. When treated with an antiviral medication called valacyclovir, 93% of them improved significantly, with fatigue scores dropping substantially. The study suggests that some cases of depression in teenagers may actually be undiagnosed ME/CFS caused by chronic viral infections.
Why It Matters
This study addresses the critical problem of ME/CFS being misdiagnosed as depression in young people, which can lead to inappropriate treatment. It provides preliminary evidence that antiviral therapy may benefit adolescents with ME/CFS and suggests a possible viral mechanism (HHV-6) that could guide future research into disease etiology and treatment.
Observed Findings
93% of valacyclovir-treated adolescents showed positive clinical response
Majority of patients (11/15) had current mood disorder diagnoses despite not meeting full DSM-IV TR depression criteria
Inferred Conclusions
Valacyclovir may be effective for treating ME/CFS in adolescents who have been misdiagnosed with depression
Chronic viral infection, particularly HHV-6 reactivation, may contribute to psychiatric symptoms in some treatment-resistant cases
A portion of pediatric treatment-resistant depression may represent undiagnosed ME/CFS rather than primary mood disorder
Remaining Questions
Why did only 7% of patients not respond to valacyclovir, and what biological differences distinguish responders from non-responders?
Does HHV-6 reactivation cause ME/CFS, or is it a consequence of immune dysfunction in CFS?
What This Study Does Not Prove
This retrospective case series without a control group cannot establish that valacyclovir causes improvement—patients may have improved naturally or due to placebo effect. The study does not prove that all treatment-resistant depression is actually ME/CFS, nor does it definitively establish HHV-6 reactivation as the cause of CFS. The small sample size and lack of randomization severely limit generalizability.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →