Excerpt from article by Theodore Henderson, MD, PhD:

My clinical work has focused on the viral and immunological pathogenesis of CFS/ME. In my clinic, I have treated over 200 adults and over 30 adolescents with what the IOM now says should be called Systemic Exertion Intolerance Disease (SEID).

While I have not published my adult cases, a case series of adolescents was published last year. What has emerged from my work is that over 85% of patients with SEID (diagnosed by Fukuda criteria) respond to antiviral therapy. Among adolescents, the outcome is better with 92% responding.

A critical second conclusion of my work is that a subset of patients diagnosed with depression — particularly treatment-resistant depression — actually had SEID. The adolescents in the case series were all referred for evaluation of depression or mood disorder. They all presented with marked fatigue, exertion induced malaise, brain fog, and impaired academic performance.

In addition, most reported daily naps and unrefreshing sleep. They had not responded to adequate trials of antidepressants and the duration of symptoms ranged from 6-96 months. There was no history of abuse or neglect, although this has been suggested as an etiology of SEID in the past.

Patients completed the Children’s Depression Inventory and the mean score was 14 (+2.83), below the typical cut-off for depression.

Patients were treated with the antiviral, valacyclovir (Valtrex), at a dose of 1000 mg twice a day. Only one patient experienced nausea and discontinued the antiviral. Improvement occurred over the course of 3-5 months. Eighty-six percent of the patients responded by 3 months, and 92% responded by 5 months. Symptoms of fatigue, exertion induced malaise, excessive sleep, napping, unrefreshing sleep, headaches, cognitive symptoms, and emotional symptoms all resolved.

The Role of Antiviral Therapy in Chronic Fatigue Treatment, by Theodore Henderson in Psychiatry advisor, March 25, 2015