Search methods
We searched the following electronic databases up to 29 September 2010: The Cochrane Library (issue 9 2010), PubMed, EMBASE
(Embase.com), CINAHL (Ebsco) and PsycINFO (PsycNET) with no language restrictions.We also reviewed: a) recent years of relevant
conferences, symposium and colloquium proceedings and abstracts; b) web-based registries of clinical trials; and c) the bibliographies
of included studies.