The relationship of fatigue to mental and physical health in a community sample.
BACKGROUND
Previous studies have shown fatigue and depression/anxiety to be highly associated with each other. The present study seeks to differentiate between fatigue and depression/anxiety and to investigate the familiality/heritability of fatigue using sib-pairs.


METHODS
The GENESiS study is a questionnaire study based in the United Kingdom that includes a five-item fatigue scale and four mental health measures (GHQ-12, EPQ-N, MASQ-AA, MASQ-HPA). Fatigue data from 10,444 sibling pairs were analysed using multivariate methods and model fitting techniques to investigate the familiality/heritability of fatigue and its relationship with the other mental health measures and physical health items.


RESULTS
Fatigue correlated highly with GHQ-12 (r=0.62, p<0.001). A principal components analysis of the fatigue scale and the GHQ-12 revealed one main component which correlated highly with mental health items, and a smaller second component which correlated modestly with physical health items. Fatigue showed a modest sibling correlation (0.09, p<0.001), and multivariate modelling revealed evidence for familial effects on fatigue that were independent of the mental health measures.


CONCLUSIONS
Fatigue showed a strong relationship with both physical illness and mental health measures. Fatigue is modestly familial and at least part of this familial factor is not shared with mental health measures.
Williamson
Richard J
RJ
Social, Genetic, Developmental Psychiatry Research, Institute of Psychiatry, PO80, 16 De Crespigny Park, Denmark Hill London SE5 8AF, UK. spjgriw@iop.kcl.ac.uk
Purcell
Shaun
S
Sterne
Abram
A
Wessely
Simon
S
Hotopf
Matthew
M
Farmer
Anne
A
Sham
Pak C
PC
D000328:Adult; D001007:Anxiety / Q000175:diagnosis / Q000453:epidemiology*; D003863:Depression / Q000175:diagnosis / Q000453:epidemiology*; D005221:Fatigue / Q000453:epidemiology* / Q000523:psychology*; D005260:Female; D006304:Health Status; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D011795:Surveys and Questionnaires