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  • Letter to the Editor
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Response to Selveraj et al.

Molecular Psychiatry volume 19, pages 964–965 (2014)Cite this article

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Our recent meta-analysis published in Molecular Psychiatry1 analysed two positron emission tomography (PET) studies and ten single photon emission tomography (SPECT) studies. We concluded that the 9R allele of the 3’UTR polymorphism of the dopamine transporter gene (SLC6A3) regulates dopamine activity in striatal brain regions independent of the presence of neuropsychiatric illness. A Letter to the Editor by Selveraj et al.2 raised several questions about our work, which we would like to address.

Our meta-analysis presented PET results from the two extant studies. The Letter is concerned with the small number of studies. We agree with this concern, which is why we addressed it as a limitation in our paper. The Letter is also concerned that we used several potentially correlated measures from the same studies. Although this issue would not bias our estimates of the standardized mean difference (SMD) effect size or the confidence intervals for each study, it could have affected our significance levels for the pooled analyses. We allay this latter concern with three observations. First, in Figure 2 from our paper readers can see that all of the 11 PET measures had SMDs >1.0, suggesting that the 9R allele is associated with increased dopamine transporter (DAT) binding. Second, we re-analysed data separately for the two brain regions that were included in both PET studies. In these pooled analyses, the SMDs are statistically significant for both caudate (SMD=0.38, z=2.4, P=0.017) and putamen (SMD=0.33, z=2.1, P=0.04). Third, our conclusions are consistent with the conclusions reported by each of the PET studies.3,4 Thus, we stand by our original conclusions but refer readers of this letter to our paper for an understanding of factors that limit the strength of these conclusions.

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References

  1. Faraone SV, Spencer TJ, Madras BK, Zhang-James Y, Biederman J . Mol Psychiatry advance online publication, 24 September 2013; doi:10.1038/mp.2013.126(e-pub ahead of print).

  2. Selvaraj S, Turkheimer F, Howes O . Mol Psychiatry advance online publication, 4 March 2014; doi:10.1038/mp.2014.15(e-pub ahead of print).

  3. Shumay E, Chen J, Fowler JS, Volkow ND . PLoS ONE 2011; 6: e22754.

    Article  CAS  Google Scholar 

  4. Spencer TJ, Biederman J, Madras BK, Dougherty DD, Bonab AA, Livni E et al. Biol Psychiatry. 2007; 62: 1059–1061.

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Authors and Affiliations

  1. Departments of Psychiatry and of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY, USA,

    S V Faraone & Y Zhang-James

  2. Department of Psychiatry, Pediatric Psychopharmacology Unit, Psychiatry Service, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA,

    T J Spencer & J Biederman

  3. Division of Neuroscience, New England Primate Research Center, Southborough, MA, USA,

    B K Madras

  4. Harvard Medical School, Boston, MA, USA,

    B K Madras

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  1. S V Faraone
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  2. T J Spencer
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  3. B K Madras
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  4. Y Zhang-James
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  5. J Biederman
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Correspondence to S V Faraone.

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Faraone, S., Spencer, T., Madras, B. et al. Response to Selveraj et al.. Mol Psychiatry 19, 964–965 (2014). https://doi.org/10.1038/mp.2014.26

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