Any medical, psychiatric or neurological illness (other than MDD)

Current or former psychopharmacological treatment

Current or former substance abuse

Pregnancy

Any implant or stainless steel graft or any other contraindications for MRI

Failure to comply with the study protocol or to follow the instructions of the investigating team

Participation in studies involving radiation exposure in the past 10 years.

Body mass index \<17 or \>30

Patient Stratification and Treatment Response Prediction in Neuropharmacotherapy Using Hybrid Positron Emmission Tomography/Magnetic Resconance Imaging (PET/MR)