Carolien Zeetsen

132 Prevalence and course of neurocognitive disorders in addiction health care Now that some important psychometric properties of the MoCA and the effects of several (demographic/substance use related) characteristics on MoCA performance are known, the next step is to further explore the prevalence and course of cognitive impairments in addiction health care. Prevalence of neurocognitive disorders Previous research pointed to an estimated prevalence of cognitive impairments in patients with SUD ranging from 30% – 80% (Copersino et al., 2009). We found a prevalence of substance–induced NCD of 31% within addiction care facilities, falling at the bottom of the estimated range. Differences in prevalence between substances were not as profound as was expected (alcohol = 34%, cannabis = 21%, stimulants = 27% and opioids = 38%). This could, however, be influenced by the high percentage of polysubstance users in our sample. In Chapter 6, a higher prevalence of cognitive impairments of 56% was found in patients referred to a detoxification unit for their GHB dependence, a group in which polysubstance use is also not uncommon (Dijkstra et al., 2017). Course of neurocognitive disorders during treatment Given the adequate test–retest reliability and the availability of parallel versions, the MoCA can potentially be used to follow the course of cognitive performance over time in patients with SUD. This was examined in Chapter 5, in a sample of 524 patients with AUD who were clinically admitted to the Centre of Excellence for Korsakoff and Alcohol–Related Cognitive Disorders, and in Chapter 6 in a sample of 103 patients entering detoxification treatment for GHB. In Chapter 5, significant differences were found in cognitive performance between three groups of patients with AUD, where patients with KS performed lowest, followed by patients with ARCI and those with AUD only, respectively. Cognitive performance improved in all three groups between intake and the sixth week of clinical admission, with a further improvement up to clinical discharge. With this, we found that all patients with AUD seem to benefit from prolonged clinical treatment. In Chapter 6, an improvement of cognitive performance on the MoCA was also found in patients with GUD, when measured before and after detoxification. When examining the MoCA–DS, patients with KS did not change on the memory domain, while patients with ARCI improved over all three assessments. In patients with GUD, the MoCA–DS memory and attention seemed to be indicative for a higher risk of relapse.