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Chronic fatigue and anxiety/depression: a twin study
Peter Roy-Byrne1, Niloofar Afari, Suzanne Ashton
1Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98104, USA.
Summary
Chronic fatigue is strongly linked to psychological distress, with this association appearing to be environmental rather than genetic. This suggests lifestyle factors may play a significant role in managing fatigue symptoms.
Area of Science:
- Psychiatry
- Genetics
- Epidemiology
Background:
- Chronic fatigue is frequently comorbid with mood and anxiety disorders.
- This suggests a potential link between chronic fatigue and psychological distress.
Purpose of the Study:
- To determine if the link between chronic fatigue and psychological distress is causal.
- To investigate if a shared genetic or environmental factor underlies this association.
Main Methods:
- Study involved 69 monozygotic (MZ) and 31 dizygotic (DZ) female twin pairs.
- One co-twin reported at least 6 months of fatigue; both completed fatigue, psychological distress (GHQ), and psychiatric interviews.
- Analyzed effects of fatigue definitions on GHQ sub-scales.
Main Results:
- Fatigued twins reported significantly higher depression, anxiety, somatic preoccupation, and social dysfunction than non-fatigued co-twins.
- Intrapair differences in symptoms were similar between MZ and DZ twins.
- Non-significant genetic covariation was observed for somatic symptoms and anxiety/insomnia.
Conclusions:
- Strong association between chronic fatigue and psychological distress in this sample.
- Evidence suggests the association is environmental, not genetic, or due to overlapping definitions.
- Any potential genetic influence is more likely related to anxiety than depression.
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