Study of twins finds genetic link to fatigue

Unexplained disabling fatigue in childhood is mainly due to genetic inheritance, a study of twins has revealed.

Chronic fatigue in young people can be disabling and is the main illness-related reason for long absences from school.

A genetic study of twins by researchers in Cardiff University's School of Medicine (Department of Psychological Medicine) found that although disabling fatigue and depression occur together, they have different genetic and environmental causes.

Participants were identified from the University's Cardiff Study of All Wales and North West of England twins. Parents of 1,468 twins and 930 older twin pairs took part in the study.

Analysis was undertaken for disabling fatigue of more than one week (short duration) and more than one month (prolonged).

The study led by Dr Tom Fowler with colleagues at Cardiff University and Professor Anne Farmer at the Institute of Psychiatry, London, found that 67% of the influences on short-duration fatigue in children and adolescents are genetic. The results suggest that prolonged fatigue is also linked to familial influences.

Dr Fowler, Department of Psychological Medicine said: "Our research found that the majority of genetic and environmental differences are specific to disabling fatigue and distinct from depression. This suggests the fatigue states in children should be considered as valid entities in their own right, and not as variants of depression."


1. The research is published in The British Journal of Psychiatry (September edition)

2.Why study twins?
Twins research at Cardiff University is very important for research into the underlying causes of behaviour. This is because of special features that twins possess. Identical twins come from the same egg and share all of their genes in common. Non-identical or fraternal twins come from two separate eggs and are no more genetically alike than non-twin brothers or sisters. That is, on average, non-identical twins share half of their genes in common (just as ordinary brothers and sisters do). These natural characteristics are very important for researchers because comparing the similarity of identical and fraternal twins allows us to separate similarity that is due to genes from similarity that is due to environmental influences. Details of the Cardiff Study of All Wales and NorthWest England Twins can be found at:

2. Cardiff University
Cardiff University is recognised in independent government assessments as one of Britainís leading teaching and research universities. Founded by Royal Charter in 1883, the University today combines impressive modern facilities and a dynamic approach to teaching and research. The Universityís breadth of expertise in research and research-led teaching encompasses: the humanities; the natural, physical, health, life and social sciences; engineering and technology; preparation for a wide range of professions; and a longstanding commitment to lifelong learning. Cardiff is a member of the Russell Group of Britainís leading research universities.

Visit the University website at:

3. School of Medicine
The School of Medicine was established in Cardiff in 1931. Until 1984 it was known as the Welsh National School of Medicine when it obtained a Royal Charter to reflect the schoolís expanded horizons, size and reputation. It later became the University of Wales College of Medicine (UWCM). In August 2004, UWCM merged with Cardiff University and the School of Medicine now forms part of the Wales College of Medicine with its four original partners in the healthcare education field. In 1995, the college introduced an exciting new medical curriculum from which students are able to combine and use knowledge, skills and judgement and develop appropriate attitudes to deliver a high standard of professional care.

The Schoolís 21 academic departments are organised into three divisions: Division of Clinical Laboratory Science, Division of Community Specialities and Division of Hospital Specialities. The pre-clinical years are spent within the School of Biosciences before moving on to the University Hospital at Heath Park for the remainder of the course.

The School has a strong international reputation for research. Research facilities have recently been enhanced with the £11m Henry Wellcome Building for Biomedical Research in Wales. The building includes 4500 square metres of state-of-the-art laboratories and equipment for research into Infection & Immunity, Cancer Biology and Psychiatric Genetics, adjacent to a purpose-built Clinical Research Facility. The Henry Wellcome Building is the largest development of its kind ever undertaken in Wales and will be a flagship for biomedical research in Wales and the Principality.

Last reviewed: By John M. Grohol, Psy.D. on 30 Apr 2016
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