TSPO and major depressive disorder: In a meta-analysis of PET studies in MDD, TSPO VT was elevated in patients with MDD compared with controls in the anterior cingulate cortex (standardised mean difference (SMD) = 0.78, 95% CI 0.41–1.16) and temporal cortex (SMD = 0.52, 95% CI 0.19–0.85).