The Effect of Diagnostic Hierarchy in Genetic Epidemiological Studies of Psychiatric Disorders-Reply

In reply  We welcome this opportunity to further clarify the concepts underlying the method that was used in our article¹ to compute the risks for late-onset MD. There appears to be some confusion regarding our definition of late-onset MD. In this article¹ as well as in our previous publications on this topic,^2,3 we have defined late-onset MD as cases in which the first onset of MD occurs after age 30 years. In other words, the event of interest is that an individual remains free of MD until age 30, and then his or her first episode of MD develops after age 30. The rationale for this definition is that we are hypothesizing that individuals who have a first onset of MD after age 30 have a different form of the disorder from individuals who have a first onset of MD before age 30. Any recurrent episode of MD occurring before