RT Journal
A1 Berney A, Leyton M, Gravel P, et al
T1 BRain regionalα-[11c]methyl-l-tryptophan trapping in medication-free patients with obsessive-compulsive disorder
JF Archives of General Psychiatry
JO Archives of General Psychiatry
YR 2011
FD July 1
VO 68
IS 7
SP 732
OP 741
DO 10.1001/archgenpsychiatry.2011.16
UL http://dx.doi.org/10.1001/archgenpsychiatry.2011.16
AB Context 
                  The hypothesis of a serotonin (5-hydroxytryptamine [5-HT]) dysfunction in obsessive-compulsive disorder (OCD) stems largely from the clinical efficacy of 5-HT reuptake inhibitors. Serotonergic abnormalities in the unmedicated symptomatic state, however, remain to be fully characterized.Objective 
                  To investigate brain regional 5-HT synthesis, as indexed by positron emission tomography and theα-[11C]methyl-L-tryptophan trapping constant (K*), in treatment-free adults meeting criteria for OCD.Design 
                  Between-group comparison.Setting 
                  Department of Psychiatry and Montreal Neurological Institute, McGill University, and Department of Psychology, McGill University Health Centre, Quebec, Canada.Participants 
                  Twenty-one medication-free patients with OCD (15 men with a mean [SD] age of 33.2 [9.3] years and 6 women with a mean [SD] age of 35.8 [7.1] years) and 21 healthy controls matched for age and sex (15 men with a mean [SD] age of 32.9 [10.1] years and 6 women with a mean [SD] age of 36.5.5 [8.6] years).Main Outcome Measure 
                  Theα-[11C]methyl-L-tryptophan brain trapping constant K*, which was analyzed with Statistical Parametric Mapping (SPM8) and with proportional normalization (extent threshold of 100 voxels with a peak threshold of P ≤ .005).Results 
                  Compared with healthy controls, the patients with OCD exhibited significantly greaterα-[11C]methyl-L-tryptophan trapping in the right hippocampus and left temporal gyrus (Brodmann area 20). In the larger subsample of all men, these same differences were also evident, as well as higher K* values in the caudate nucleus. Individual differences in symptom severity correlated positively with K* values sampled from the caudate and temporal lobe of the patients with OCD, respectively. There were no regions where the patients exhibited abnormally low K* values. Volumetric analyses found no morphometric alterations that would account for the group differences.Conclusion 
                  The results support previous reports of greater striatal and temporal lobe activity in patients with OCD than in healthy controls and suggest that these disturbances include a serotonergic component. Previously reported glucose metabolic disturbances in OCD involving the orbitofrontal and cingulate cortices, in comparison, might reflect postsynaptic changes in the serotonergic system.