Date	Event	Description
14 March 2017	Feedback has been incorporated	Feedback by Dr Gregory (via Cochrane Feedback mechanism, supplied to CDPLPG by Wiley 14 February 2017) incorporated. Changes included: ‐ correction of wording within Summary of main results; ‐ new paragraph inserted within Quality of the evidence; ‐ 'Risk of bias' rating changed for Gregory 2008 ('Risk of Bias table > Attention bias'); and ‐ wording changed accordingly in Other potential sources of bias. Conclusions of review unchanged.
31 January 2013	Amended	Correction of data extraction error in relation to Davidson 2006 (analyses 1.7.4 and 1.9.5). Conclusions unchanged.
1 November 2012	Amended	Minor edit in the description of the exclusion criteria in two studies.
6 June 2012	New citation required and conclusions have changed	Change in conclusions New authorship Accumulation of changes: change in methods section; rewriting of background section; changing of conclusions due to new identified evidence
10 October 2010	New search has been performed	New search