Carolien Zeetsen

127 CHAPTER Summary and general discussion 7 Summary and general discussion Chronic substance (ab)use has acute and long–term effects on cognitive functioning. The presence of substance–induced NCD also affects the course and results of treatment. For instance, having NCD is predictive of higher drop–out rates during treatment and less reported abstinence. However, patients and clinicians are not always aware of these cognitive deficits, and subjective reports of cognitive complaints do not correlate well with the actual cognitive test performance. This illustrates that it is important to diagnose substance–induced NCD using performance–based neuropsychological testing. As administering an NPA in all patients entering addiction treatment is not feasible, because it is time consuming, relatively expensive and needs highly experienced clinicians and motivation from the patient, there is need for shorter instruments to measure cognitive (dys)function in patients with SUD. Such a cognitive screening instrument should meet certain criteria, for instance, it should have a short administration time, have an easy to interpret score and be relatively independent of education, language or culture. It should have good psychometric properties like test–retest and inter–rater reliability, and good concurrent and predictive validity with high levels of sensitivity and specificity. Above all, it must be easy to score and be acceptable in administration for both the clinician and the patient. A potentially promising cognitive screening instrument for detecting substance– induced NCD is the MoCA. The main objective of this thesis was to investigate if the MoCA is indeed a feasible and valid cognitive screening instrument that can bridge the aforementioned gap between knowledge – exactly knowing what needs to be done to plan well indicated treatment – and clinical reality – realizing an NPA for each individual is impossible. In this chapter, I will present and discuss the main findings and their clinical implications, starting with the psychometric properties of the MoCA. Next, findings on the applicability of the MoCA in addiction health care will be discussed, followed by the prevalence and course of NCD in addiction health care. Finally, I will discuss the strengths and limitations, clinical considerations and provide guidelines for future research. Psychometric properties of the Montreal Cognitive Assessment Reliability A cognitive screening instrument should have excellent reliability, which is the overall consistency of a measure, meaning that it should produce similar results under consistent conditions. There are several forms of reliability. In Chapter 2 both alternate–form and test– retest reliability of all three Dutch translations of the MoCA were examined in a sample of 210 healthy participants aged 18–70. Regarding the alternate–form reliability, all three versions of de MoCA were found to be largely equivalent, based on MoCA–TS and –MIS.