Serotonin-1A receptor alterations in depression: a meta-analysis of molecular imaging studies

BACKGROUND: Postmortem studies of people who have successfully committed suicide and people with depression have implicated the serotonin-1A (5-HT(1A)) receptor system in the pathophysiology of depression. Several molecular imaging studies have investigated alterations in 5-HT(1A) receptors in patients with depression using positron emission tomography and have reported conflicting results. METHODS: We performed a meta-analysis of studies investigating the relationship between depression and 5-HT(1A) binding. We conducted a comprehensive search of Medline, Embase, ScienceDirect, Scopus and Springer databases for relevant studies published between January 1999 and October 2015. The meta-analysis was conducted in accordance with the Meta-analysis of Observational Studies in Epidemiology guidelines. RESULTS: Ten studies were included, comprising 218 patients with depression and 261 healthy controls. The results of these studies indicated a reduction in 5-HT(1A) receptors in mesiotemporal cortex, yielding a summary effect estimate of -0.8 (95 % CI −1.36, −0.24). Smaller reductions were reported in 5-HT(1A) receptor binding in the hippocampus, raphe nuclei, insular, anterior cingulate cortex and occipital cortex of people with depression. No clear effect of depression on 5-HT(1A) receptors was detected in the amygdala. CONCLUSIONS: Reduced 5-HT(1A) receptor binding was associated with the pathology of depression and predicted altered serotonergic neurotransmission in various brain regions. These findings increase our understanding of the neurophysiological processes underlying depression. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12888-016-1025-0) contains supplementary material, which is available to authorized users.