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. 2012 Sep 12;7(9):e44275. doi: 10.1371/journal.pone.0044275

Figure 2. Association between ADHD and the D4 dopaminergic receptor gene in initial and subsequent studies.

Figure 2

The strength of the association (i.e. the odd ratio, the ratio of prevalence of the 7R allele of this DRD4 gene in ADHD children versus control children) in each study is given in the ordinate. In 1996 LaHoste and coworkers published the first study associating ADHD with the DRD4 gene [18]. This initial study reported an odd ratio of 3.01. Subsequent case-control studies reported smaller odd ratio (data from table 1A in [47]). According to two recent meta-analyses [46], [47], ADHD is still considered to be significantly associated with the DRD4 gene although this association confers a much smaller risk than initially thought (odd ratio indicated by a diamond). Filled circles indicate scientific studies echoed by newspapers (number of media articles indicated in parentheses). Empty circles and diamonds indicate that the publication has not been echoed by newspapers.