Harmen Beurmanjer

158 Supplements People using GHB recruited from the general population Reference Aim Study design Methods Anderson et al., 2010 To investigate reasons that might explain why the trend of declining GHB use is not paralleled internationally. Anonymous internet- based survey (13-item created GHB survey instrument) from 30-10- 2007 through 15-3-2008. N=155 (70 U.S. and 85 non-U.S. responders from 15 different countries), survey respondents (≥18 years) who reported any lifetime or current use of GHB. Recruited through social networking internet sites by posting recruitment notices. The Brown University Digest of Addiction Theory and Application, 2007 To obtain information on consumption habits, experiences, and beliefs of recreational GBH users. Focus groups (10) between March and December 2004. N=51, recruited through flyers and a website advertisement. People aged 18 to 52 years who reported using GHB at least once in the previous 12 months. Participants generally lived in the San Francisco area (United States). Degenhardt et al., 2002; Degenhardt et al., 2003 To examine characteristics of GHB users, GHB and other drug use patterns, and harms associated with GHB use; To examine correlates, context and risk perceptions regarding GHB overdose among recreational GHB users. Cross-sectional survey (by structured interviews) between January – June 2001. N=76, recruited through various methods (e.g. snowball, news). Participants who used GHB in the previous 6 months. Participants lived in Melbourne and Sydney, Australia. Degenhardt et al., 2008 To study patterns and correlates of GHB and ketamine use amongst a representative population sample of Australians. National Drug Strategy Household Survey conducted in 2004. Two methods were used: (1) drop and collect method (2) and computer assisted telephone interview. N=115, respondents (Australian, 14 years and older) who ever and in the preceding 12-months used GHB or ketamine.