Date	Event	Description
18 March 2008	Amended	Converted to new review format.
30 January 2008	New citation required and conclusions have changed	Substantive amendment.
30 January 2008	New search has been performed	Two new trials have been added: one pharmacological intervention making a total of 10 pharmacological trials (12 comparisons), and one psychological intervention making a total of four trials. Seven trials require more information before they can be assessed for inclusion in the review (down from 14 in the previous version). Seven trials appear to meet review inclusion criteria but information is not available in a format suitable for pooling. Four trials are ongoing (up from two in the previous version).