A search of the following databases for eligible studies was performed from inception to the present on 10 January 2013: Medline, Embase, PsychInfo and Social Policy and Practice. The final search terms used in Psychinfo are presented in box 1. The database search was complemented by backward searching, involving screening the reference lists of included studies, and forward searching of subsequent citations of these papers. Further relevant studies were identified by contacting 20 experts in this subject area of young people's drinking, and by screening the references of a recent, related review which also informed the design of the present study.16 Screening of abstracts was undertaken by the first author and both authors independently reviewed selected full texts for suitability of inclusion. Box 1Database search strategy used in Ovid SP to search Psychinfo.(“age at onset” or “age of onset” or “ first drink” or “age at first use” or “age at initiation” or “age of initiation” or “early initiation”).ab.age of onset.sh.1 or 2(“drinking” or “alcohol”).ab.(alcohol or drinking).sh.4 or 53 and 6(“alcohol-related problems” or “alcohol related problems” or “alcohol abuse” or
