Notably, the study of SV2A‐specific binding to synapses using 11C‐UCB‐J‐PET will allow us to examine synapses directly in vivo, and we expect that it will lead to the identification of a new objective marker or outcome measure of the efficacy of ketamine for treatment‐resistant depression, or of other clinical trials of therapies targeting synapse restoration. This evidence concerns the gene SV2A and depressive disorder.