The serotonin transporter in depression: Meta-analysis of in vivo and post mortem findings and implications for understanding and treating depression.

Background: Altered serotonin transporter levels have been reported in blood and brain of patients with major depressive disorders. However, the strength and consistency of the evidence for altered serotonin transporter availability in major depressive disorder is not clear.

Methods: To address this, a comprehensive meta-analysis was conducted of all available in vivo neuroimaging and post mortem studies reporting serotonin transporter availability in patients with depression compared with healthy controls.

Effect of BDNF val(66)met polymorphism on declarative memory and its neural substrate: a meta-analysis.

Brain derived neurotrophic factor (BDNF) is a critical component of the molecular mechanism of memory formation. Variation in the BDNF gene, particularly the rs6265 (val(66)met) single nucleotide polymorphism (SNP), has been linked to variability in human memory performance and to both the structure and physiological response of the hippocampus, which plays a central role in memory processing. However, these effects have not been consistently reported, which may reflect the modest size of the samples studied to date.