Border R et al found evidence suggesting that early hypotheses about depression candidate genes were incorrect. The scientists claimed that a large number of associations reported in the depression candidate gene literature are likely to be false positives. The research evaluated 18 candidate genes that have been most commonly studied linked to depression, with SLC6A4
being the chief among them. Using data from large groups of participants, ranging from 62,000 to 443,000 people, the researchers investigated whether any versions of these genes were more common among people with depression. The authors conducted a series of preregistered analyses examining candidate gene polymorphism main effects, polymorphism-by-environment interactions, and gene-level effects across a number of operational definitions of depression (lifetime diagnosis, current severity, episode recurrence) and environmental moderators (sexual or physical abuse during childhood, socioeconomic adversity). The findings showed no clear evidence for any candidate gene polymorphism associations with depression phenotypes or any polymorphism-by-environment moderator effects. The researchers concluded that depression candidate genes were no more associated with depression phenotypes compared to non-candidate genes.
Source: The American Journal of Psychiatry 8 Mar 2019 https://doi.org/10.1176/appi.ajp.2018.18070881