PET and SPECT have suggested that there is an age-related decline of up to 10% per decade in the availability of brain serotonin transporter (SERT) in healthy subjects, starting as early as the age of 20 y. The aim of the present study was to verify these findings in young subjects. METHODS: The equilibrium specific-to-nonspecific partition coefficient V''(3) of the SERT ligand (11)C-(+)McN5652 was obtained for 29 healthy subjects aged 18-33 y. V''(3) was tested for age dependence by linear regression analysis using both a volumes-of-interest approach and voxel-based statistical parametric mapping. The sex of the subject and the season of year were considered nuisance variables. RESULTS: Age had no significant effect on V''(3). The power for the detection of an age-related decline in V''(3) of the magnitude reported previously was 0.917. CONCLUSION: These findings indicate that age is not a relevant confounding factor for SERT availability as measured by (11)C-(+)McN5652 PET in healthy adults up to the age of about 35 y.
