Strength of association is shown as an estimate of the odds ratio without confidence intervals. At top are eight topics in which the results of the first study differed beyond chance (P < 0.05) when compared with the results of the subsequent studies. The bottom shows eight topics in which the first study did not claim formal statistical significance for the genetic association, but formal statistical significance was reached by the end of the meta-analysis. (Adapted from J.P. Ioannidis et al.,
The first published study linking gene to disease is often far from the last word on the subject. Marc-Antoine Crocq, a psychiatrist with the Centre Hospitalier de Rouffach in France, learned this firsthand after leading a 1992 study on a mutation in the dopamine D3 receptor in the brain.1 The study found that people with two copies of the mutation have a schizophrenia risk roughly ...
