Research abstract:

Objectives:
Previous studies have consistently shown increased rates of childhood adversity in chronic fatigue syndrome (CFS). However, such aetiopathogenic studies of CFS are potentially confounded by co-morbidity and misdiagnosis particularly with depression.

We used a modelling approach with existing data and data generated in our examination of the rates of childhood adversity in a sample of CFS patients who had no lifetime history of depression.

Methods:
The childhood trauma questionnaire (CTQ) was completed by a sample of 52 participants and 19 controls with chronic fatigue syndrome who did not meet criteria for a psychiatric disorder (confirmed using the Structured Clinical Interview for DSM-IV). Subsequently, Mediation Analysis (Baye’s Rules) was used to establish the risk childhood adversity poses for CFS with and without depression.

Results:
In a cohort of CFS patients with depression robustly excluded, CTQ scores were markedly lower than in all previous studies and, in contrast to these previous studies, not increased compared with healthy controls.

Post-hoc analysis showed that CTQ scores correlated with the number of depressive symptoms during the lifetime worst period of low mood. The probability of developing CFS given a history of childhood trauma was shown to be 4%, a two-fold increased risk compared to the general population. However, much of this risk is mediated by the concomitant development of major depression.

Discussion:
The data suggests that previous studies showing a relationship between childhood adversity and CFS may be mediated by depression

Rethinking childhood adversity in chronic fatigue syndrome, by James E Clark, Sean Davidson, Laura Maclachlan, Megan Lynn, Julia L Newton, Stuart Watson in PeerJ, December 7, 2015 [NOT PEER-REVIEWED]