A positron emission tomography (PET) imaging agent may be able to reveal the efficacy of specific treatments for major depressive disorder, reports News-Medical.Net.

The PET tracer 11C-DASB targets the serotonin transporter protein (5-HTT) in the amygdala of the brain, which is important for emotional processing. The drug escitalopram, a selective serotonin reuptake inhibitor (SSRI), can be an effective MDD treatment, but not for all patients. A PET scan with 11C-DASB can indicate which patients will benefit by measuring the level of 5-HTT present before treatment.