Abstract ISSDP 2011 Hilgunn Olsen & Anne Line Bretteville-Jensen Do injection rooms increase risk behavior? - An analysis of heroin dosage administered inside and outside an injection room in Oslo, Norway Background: Traditionally, Norwegian drug policy has been strict and aimed at a drug free society. Harm-reducing measures have remained controversial. Syringe exchange programmes were, nevertheless, introduced in the late 80s, methadone maintenance treatment in the 90s and a supervised injection room was opened in Oslo in 2005. The latter exacerbated some of the dilemmas inherent in harm-reducing measures because illegal drugs are carried and administered in the presence of public health and social workers. One common objection has been that injection rooms can increase risk behaviour because of staff surveillance. This is based on the assumption that drug users will try to get “the optimal high”, and therefore inject higher doses, because of the safer conditions in the injection room setting. Aim: To improve our knowledge of how harm-reducing measures influence clients’ injection behaviour, we will explore a unique data set on heroin doses and overdoses in a Norwegian injection room. In addition to a description of clients, average heroin doses, overdose prevalence etc., we examine whether the heroin doses reported at the injection room differ from average doses reported by heroin users outside the injection room. We further investigate 1) whether recommendations by staff to reduce particularly risky heroin doses and 2) overdose incidence on the premises influence the doses injected by drug users on subsequent visits. Data: The paper is based on two different data sets collected from amenities provided for Oslo’s injecting drug users: Oslo’s public injection room and the main needle exchange service. Both data sets cover the 2005-2008 period. The injection room data were collected by staff on every single visit to the facility, comprising 46, 995 visits by 1, 155 separate users. The second data set is based on personal interviews of 635 users visiting a needle-exchange service in Oslo. Results: Preliminary results show that the average reported amount of heroin injected in the injection room was significantly lower than the average of the latest heroin dose injected and reported by users of the needle exchange. Only a fraction of the injection room users, however, report reduced heroin doses after staff intervention and overdose experiences.