Harmen Beurmanjer

162 Supplements People using GHB recruited from the general population (Continued) Reference Aim Study design Methods Kim et al., 2007; Kim et al., 2008 To assess the performance characteristics of the survey instrument, high risk behaviours in relation to GHB related hospital treatment, and association between socio-demographic characteristics and risk behaviours. Survey by FORGE (Factors in Overdose Research into GHB Effects). A structured, telephone-administrated questionnaire. N=146, 131 interviews (90%). Kim et al., 2008: N=125, United States. One group (N=14) identified through California Poison Control System (CPCS) surveillance (GHB-users needing medical attention in health care facility). Second group (N=132) was recruited via internet postings, flyers in public places, physician referrals, and by snowball sampling. Korf et al., 2014 To identify factors which increase the risk of overdosing (OD) with GHB among recreational drug users. Survey (by interviews) between February 2012 and June 2012. N=45, participants (≥ 18 years) with a lifetime prevalence of GHB use at 25 or more occasions, and at 1 or more occasions in the past 12-months. Participants were recruited through ethnographic fieldwork in public (clubs, festivals) and private settings (e.g. afterparties), and through snowball referrals in the Netherlands. Miotto et al., 2001 To examine patterns of GHB use, its effects, and withdrawal. Survey (interview) in 2 parts: one part reviewed demographic and psychiatric treatment history. Second part addressed GHB-use. N=42 (120 responders, 42 came in for interview), recruited by advertisements for regular GHB-users in two local English language newspapers in Los Angeles (United States).