Carolien Zeetsen

21 CHAPTER General introduction 1 Consequences of neurocognitive disorders for treatment The presence of substance–induced NCD affects the course and results of addiction treatment. For instance, having NCD predicts higher drop–out rates during treatment (Teichner et al., 2002), and decreases the likelihood of attending all therapy sessions (Copersino et al., 2012). Treatment results are worse for patients with NCD than for those without, including lower treatment retention and less reported abstinence (Aharonovich et al., 2003; Aharonovich et al., 2006). Also, patients with NCD may not recognize their problematic substance use and show less intention to stop using (Severtson et al., 2010). Also, they have lower self–efficacy, which is in turn predictive of less abstinent days and larger amounts of use on a using day (Bates et al., 2006). Finally, patients with substance– induced NCD show higher relapse rates (Dijkstra et al., 2017). If SUD treatment takes NCD into account, this may lead to improvement of cognitive functioning (Forsberg & Goldman, 1987; Roehrich & Goldman, 1993; Sofuoglu et al., 2010). Therefore, the consequences of having NCD and entering ‘regular’ addiction treatment, show the need to diagnose early. Assessment of neurocognitive disorders: evidence and challenges Although we can assume that NCD occurs in a large number of patients with SUD, it is often a challenge to identify in clinical practice patients who actually have NCD. For instance, self–report measures of cognitive function are feasible in this group, but do not provide a valid estimate of the patients’ cognitive status, as patients are not always aware of their cognitive deficits. This is also illustrated by a lack of correlation between objectively measured and subjectively experienced cognitive deficits (Horner et al., 1999). More recently, Walvoort et al. (2016) also found that a higher degree of illness insight is associated with better cognitive functioning. An important finding, as this implies that even clinicians are not aware of patients having cognitive deficits without neuropsychological test results backing up the observations. This demonstrates the importance of properly diagnosing substance–induced NCD based on a standardized neuropsychological assessment (NPA). Neuropsychological assessment Administration of an NPA has several drawbacks. It is time consuming, relatively expensive, not always available and it requires highly experienced clinicians and patients who are motivated to participate in an NPA. This motivation is even more tested when a period of abstinence is first needed. For instance, patients should be able to remain abstinent for a minimal period of six weeks to minimize the intoxicating effects of alcohol in the brain (Walvoort et al., 2013). Therefore, administering an NPA to all patients entering addiction treatment is not feasible.