Carolien Zeetsen

130 Applicability of the Montreal Cognitive Assessment in addiction health care Although it has often been argued that performance on cognitive screening instruments should not be affected by demographic variables, in practice such effects have been reported for many cognitive instruments. Therefore, it is important to examine the influence of demographic variables, making it possible to take them into consideration when interpreting results. Effect of demographic variables The MoCA takes the effect of years of education into account to some extent, by awarding an additional point to the MoCA–TS for those with twelve years of education or less. There is some evidence that other demographic variables also affect MoCA performance, but these have not been extensively studied for individuals under 65. Therefore, the effects of demographic variables age, sex, level of education and estimated premorbid intelligence on MoCA performance were investigated in healthy participants (Chapter 2) and in patients with SUD (Chapters 3 and 4). Regarding age, it was found both for healthy participants and for patients with SUD (specifically alcohol and cannabis) that older individuals performed worse on the MoCA–TS than younger participants. In healthy participants this was also found for the MoCA–MIS. Comparing these results to other studies shows that they are in agreement with previous findings in patients with AUD aged 18 and older (Alarcon et al., 2015), in a sample of healthy controls aged 25–91 (Freitas et al., 2012), and in several samples of adults aged 50 and older (Zheng et al., 2012; Malek–Ahmadi et al., 2015; Oren et al., 2015). Originally, however, Nasreddine et al. (2005) did not find an effect of age in a sample of geriatric patients aged 55–85, possibly due to the small age range. Strikingly, a positive correlation was found between age and the MoCA–TS for patients using stimulants (Chapter 4). This may be a consequence of the primarily enhancing effects of stimulant intoxication at low doses (Scott et al., 2007; Spronk et al., 2013). Regarding sex, it was found that women outperformed men on the MoCA–MIS, but no sex differences were found on MoCA–TS. The difference between men and women has been objectified in episodic memory functioning in childhood ages (Gur et al., 2012) and in particular working memory tasks in adults (Saylik et al., 2018). In other studies regarding the MoCA, only one study also found a significant, but small sex difference on the delayed recall item in Spanish participants aged 18 and older (Ojeda et al., 2016). Due to the small effect size, an adjustment for sex is not needed.