Competing interests
G. Kirov has received a grant from the Janssen Research Foundation for the collection of families with psychiatric disorders in Bulgaria for genetic studies. The current work is completely independent of that study, we have not informed the company of our work with topiramate, and have not shown them the manuscript. The Mood Disorders Clinic in Cardiff does not receive financial or any other support from Janssen-Cilag (Janssen-Cilag is the producer of topiramate). G. Kirov has received honoraria for lecturing from Eli Lilly and AstraZeneca and grant support from the Wellcome Trust, MRC, London, and Sanofi Synthelabo. J. Tredget's post is funded by AstraZeneca. None of the financial support received by the authors has been in any way related with the work described in this paper.