We would like to thank the Health Research Board (HRB) and the National Drug Treatment Centre for providing data on drug treatment patterns. In particular, we would like to thank the following people for their ongoing support in providing data throughout the project: Dr. Suzi Lyons (HRB), Dr. Ann Marie Carew (HRB), Kelly Hatch (National Drug Treatment Centre), Niamh Thornton (National Drug Treatment Centre), Bill Ebbitt (National Drug Treatment Centre). Special thanks also to Sarah Hamza and Caoimhe Flynn for proof reading and assistance throughout the project.