1. Department of Psychiatry , , New Haven, CT , USA
2. School of Medicine, Yale University , , New Haven, CT , USA
3. Department of Biostatistics, School of Public Health, Yale University , New Haven, CT , USA
4. Psychology Service, Veterans Affairs Connecticut Healthcare System , West Haven, CT , USA
5. Yale Positron Emission Tomography (PET) Center, School of Medicine, Yale University , New Haven, CT , USA
6. Department of Radiology and Biomedical Imaging, School of Medicine, Yale University , New Haven, CT , USA
7. Department of Biomedical Engineering, School of Medicine, Yale University , New Haven, CT , USA