AlteredSelfCDC07pdf.pdf

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REVIEW

An extended concept of altered self: Chronic fatigue

and post-infection syndromes$

F.

Chronic Viral Diseases Branch, Division of Viral and Rickettsial Diseases,

National Center for Zoonotic,

Vectorborne, and Enteric Diseases, Centers for Disease Control and

Prevention, Atlanta, GA 30333, USA

Received 2 July 2007; received in revised form 3 October 2007; accepted 17

November 2007

KEYWORDS

Altered self;

Sickness behavior;

Chronic fatigue

syndrome;

Post-infection

fatigue;

Interoception;

Functional brain

imaging

Summary

Sickness behavior in active infectious diseases is defined here as the

responses to cytokines

and other mediators of inflammation as well as the adaptability of a

pre-existing

integrated immunological, psychological, neurological, and philosophical

self. These

complex behaviors are biologically advantageous to the afflicted individual,

but they also

impact surrounding individuals. If chronic conditions, such as chronic

fatigue syndrome or

post-infection fatigue, exhibiting these behaviors follow infection in the

absence of

ongoing changes in immunological self associated with an active infection or

subsequent

injury, they are currently considered illness states rather than true

diseases. Selfreferential

recognition (interoception) of bodily processes by the brain and subsequent

unconscious and conscious adaptive responses arising in the brain, i.e., in

the endocrine

system and immune systems, which are initiated during the infection and

would normally

lead to positive maintenance, may become maladaptive and lead to an ‘‘

extended altered

self state.’’ Exploratory measurements of such alterations using a ‘‘

top-down’’ approach

such as monitoring responses to appropriate challenges can be obtained using

functional

brain imaging techniques. Once identified, processes remediable to

biological/pharmacologic

and/or psychological intervention can be targeted in directed trials.

Published by Elsevier Ltd.