We appreciate the opportunity to respond to the letter by Drs Joober, Sengupta, and Schmitz. We were attempting to replicate a study conducted by Caspi et al1 and we therefore sought to replicate the methods and measures they used insofar as we could. We used logistic regression to model risk for conduct disorder because Caspi et al used logistic regression to model risk for conduct disorder. Logistic regression also has the advantage of being relatively robust to scaling artifacts (heteroscedasticity), which can be an issue when modeling interactions. We created a simple count variable of each measured adversity to obtain a quantitative measure of severity of exposure to family adversity. In practice, the architecture of familial adversity is likely to be complex and we would welcome efforts to address this issue in larger samples with greater power. The issue of statistical power is not a trivial one and our sample size was relatively modest (n = 514 male twins). We therefore published our data in a transparent way to permit evaluation and reanalysis. The reported interaction was not estimated on the basis of a single data point and 1-sided significance tests should be conducted when there is a clear directional hypothesis based on prior work. Ultimately, functional studies will be required to validate observed statistical associations, including statistical interactions, consistent with the presence of genotype × environment interactions. Until then, meta-analysis of published studies provides one way of attempting to summarize the strength of statistical evidence across studies of variable size.2
Register and get free email Table of Contents alerts, saved searches, PowerPoint downloads, CME quizzes, and more
Subscribe for full-text access to content from 1998 forward and a host of useful features
Activate your current subscription (AMA members and current subscribers)
Purchase Online Access to this article for 24 hours
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
Thank you for submitting a comment on this article. It will be reviewed by JAMA Psychiatry editors. You will be notified when your comment has been published. Comments should not exceed 500 words of text and 10 references.
Do not submit personal medical questions or information that could identify a specific patient, questions about a particular case, or general inquiries to an author. Only content that has not been published, posted, or submitted elsewhere should be submitted. By submitting this Comment, you and any coauthors transfer copyright to the journal if your Comment is posted.
* = Required Field
Disclosure of Any Conflicts of Interest*
Indicate all relevant conflicts of interest of each author below, including all relevant financial interests, activities, and relationships within the past 3 years including, but not limited to, employment, affiliation, grants or funding, consultancies, honoraria or payment, speakers’ bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued. If all authors have none, check "No potential conflicts or relevant financial interests" in the box below. Please also indicate any funding received in support of this work. The information will be posted with your response.
Some tools below are only available to our subscribers or users with an online account.
Download citation file:
Web of Science® Times Cited: 1
Customize your page view by dragging & repositioning the boxes below.
More Listings atJAMACareerCenter.com >
and access these and other features:
Enter your username and email address. We'll send you a link to reset your password.
Enter your username and email address. We'll send instructions on how to reset your password to the email address we have on record.
Athens and Shibboleth are access management services that provide single sign-on to protected resources. They replace the multiple user names and passwords necessary to access subscription-based content with a single user name and password that can be entered once per session. It operates independently of a user's location or IP address. If your institution uses Athens or Shibboleth authentication, please contact your site administrator to receive your user name and password.