What happens when the authors of studies linking candidate gene polymorphisms to response to drug consumption tried to replicate their own research?
As many of you know, the saga of replication problems continues unabated in social and personality psychology. The most recent dust up being over the ability of some researchers to replicate Dijksterhuis’ professor prime studies and the ensuing arguments over those attempts.
While social and personality psychologists “discuss” the adequacies of the replication attempts in our field a truly remarkable paper was published in Neuropsychopharmacology (Hart, de Wit, & Palmer, 2013). The second and third authors have a long collaborative history working on the genetics of drug addiction. In fact, they have published 12 studies linking variations in candidate genes, such as BDNF, DRD2, and COMT to intermediary phenotypes related to drug addiction. As they note in the introduction to their paper, these studies have been cited hundreds of times and would lead one to believe that single SNPS or variations in specific genes are strongly linked to the way people react to amphetamines.
The 12 original studies all relied on a really nice experimental paradigm. The participants received placebos and varying doses of amphetamines across several sessions, and the experimenters and participants were blind to what dose they received. The order of drug administration was counterbalanced. Then, participants rated their drug-related experience over the few hours that they stayed in the lab. Across the 12 studies the authors, their post docs, and graduate students published studies linking the genetic polymorphisms to outcomes like feelings of anxiety, elation, vigor, positive mood, and even concrete outcomes such as heart rate and blood pressure. Continue reading

