[1] Charite Univ Med Ctr, Dept Psychiat, CCM, Berlin, Germany
[2] Univ Tubingen, Dept Psychiat, D-7400 Tubingen, Germany
[3] Univ Tubingen, Dept Nucl Med, Tubingen, Germany
[4] Cent Inst Mental Hlth, Dept Addict Behav & Addict Med, D-6800 Mannheim, Germany
[5] Univ Heidelberg, Heidelberg, Germany
[6] Univ Tubingen, Dept Radiopharm, Tubingen, Germany
[7] Univ Tubingen, PET Ctr, Tubingen, Germany
[8] Univ Aachen, Rhein Westfal TH Aachen, Dept Psychiat & Psychopharm, D-5100 Aachen, Germany