Brain 5-HT(1A) receptor binding in chronic fatigue syndrome 
measured using positron emission tomography and [(11)C]WAY-100635.

Biol Psychiatry. 2005 Feb 1;57(3):239-46.

Cleare AJ, Messa C, Rabiner EA, Grasby PM.

Section of Neurobiology of Mood Disorders, Division of Psychological 
Medicine, Institute of Psychiatry and Guy-s, King-s and St. Thomas- 
School of Medicine; National Affective Disorders Unit, Bethlem Royal 
and Maudsley Hospitals.

PMID: 15691524


BACKGROUND: Research from neuroendocrine challenge and other indirect 
studies has suggested increased central 5-HT function in chronic fatigue 
syndrome (CFS) and increased 5-HT(1A) receptor sensitivity. We assessed 
brain 5-HT(1A) receptor binding potential directly using the specific 
radioligand [(11)C]WAY-100635 and positron emission tomography (PET).

METHODS: We selected 10 patients from a tertiary referral clinic who 
fulfilled the CDC consensus criteria for CFS. To assemble a homogenous 
group and avoid confounding effects, we enrolled only subjects who were 
completely medication-free and did not have current comorbid psychiatric 
illness. We also scanned 10 healthy control subjects.

RESULTS: There was a widespread reduction in 5-HT(1A) receptor binding 
potential in CFS relative to control subjects. This was particularly 
marked in the hippocampus bilaterally, where a 23% reduction was observed.

CONCLUSIONS: There is evidence of decreased 5-HT(1A) receptor number or 
affinity in CFS. This may be a primary feature of CFS, related to the 
underlying pathophysiology, or a finding secondary to other processes, 
such as previous depression, other biological changes or the behavioral 
consequences of CFS.