Harmen Beurmanjer

12 Chapter 1 with GUD (Raposo Pereira, McMaster, Polderman, de Vries, et al., 2018a; Raposo Pereira, McMaster, Polderman, DAT de Vries, et al., 2018). Moreover, in this cross-sectional study GHB-induced comas were also associated with alterations in long-term memory networks and lower hippocampus/lingual gyrus activity while performing memory tasks (Raposo Pereira, McMaster, Polderman, de Vries, et al., 2018a). These cogntive problems could also influence the development of GUD, as deminished cognitive function has also been connected to increased use in other substance use disorders. While most recreational users take exact doses measured in millilitres, dependent users often just take a sip of a bottle when they feel they need the next dose. By the time that users present themselves at addiction care facilities there is usually a complete loss on control over GHB use, using every 1-3 hours and around 85 ml GHB per day. Poly substance use is common, mainly co-use of amphetamines and sedatives such as benzodiazepines (Dijkstra et al., 2017; Kamal, Dijkstra, Loonen, & De Jong, 2016). Co morbid psychiatric disorder such as anxiety, mood and personality disorders are also frequently reported (Dijkstra et al., 2017). In the literature the best described part of GUD is the GHB withdrawal syndrome. This syndrome often has a fulminant course with rapid onset and swift progression of severe withdrawal symptoms. GHB withdrawal symptoms include: tremor nausea, vomiting, tachycardia, insomnia, diaphoresis, anxiety and nystagmus. When the withdrawal is not properly addressed adverse events such as hypertensive crisis, severe agitation, delirium and epileptic seizures can occur (Galloway et al., 1994; Gonzalez & Nutt, 2005; McDonough, Kennedy, Glasper, & Bearn, 2004; O. C. Snead & Gibson, 2005; M. Van Noorden, Kamal, Dijkstra, Brunt, & De Jong, 2016). Little is known about the prevalence of GUD due to the absence of surveillance and systematic reporting mechanisms, and there is a reasonable chance of underestimation due to frequent home use (Tibor M. Brunt, Koeter, Hertoghs, van Noorden, & van den Brink, 2013). In their sample of regular GHB users, Miotto et al. (K. Miotto et al., 2001) reported that 21% were physically dependent (DSM-IV-TR) on GHB. Degenhardt et al. (Louisa Degenhardt, Darke, & Dillon, 2003) reported 4% dependence on GHB among a sample of recreational GHB users. However, the majority of participants in the Degenhardt et al. study had only recently started using GHB and used GHB less frequently than the participants in the Miotto et al. study. Due to the absence of longitudinal studies, little can be said about the transition from recreational use to addiction. In recent years the number of studies on patients with GUD applying for detoxification has slowly increased. In the Netherlands it is estimated that the number of patients with GUD seeking help has increased from 4 per 100,000 inhabitants in 2007 to 48 per 100,000 inhabitants in 2014. The number of patients admitted to Dutch addiction treatment centres for GHB detoxification increased from 63 patients in 2008 to 1200 patients in 2015, about 1.2% of the total population in addiction treatment (M. S. van Noorden, Mol, Wisselink, Kuijpers, & Dijkstra, 2017).