Géraud Dautzenberg

General introduction

it a different problem? There are indications that in older patients with, for example, a bipolar or depressive disorder, a different manifestation or even a type of this disorder may be at hand (Sajatovic et al. , 2015; Aizenstein et al. , 2016). In particular, if the disorder arises only for the first time at a later age (i.e. late onset or very late onset), the expected neurodegenerative disorders that occur with advancing age can also play a role, in both numbers (prevalence) and severity. One has to bear in mind that the prevalence of dementia is already up to 10% from 65 years of age and above (Volksgezondheidenzorg. info, 2019; ‘2020 Alzheimer’s disease facts and figures’, 2020). Our colleagues, who also deal with neurodegenerative disorders (neurologists, clinical geriatricians), normally do not often have other psychiatric diseases among their referrals that cause cognitive impairment. Of course, they still need to be aware of them. In The Netherlands, referrals to old age psychiatry consist of a mix of neurodegenerative and other psychiatric disorders, such as depression, bipolar disorders, schizophrenia, and severe anxiety disorders, all of which can be accompanied by poor (long-term) cognitive functioning (Bierman et al. , 2005; Schouws et al. , 2012; Baune and Renger, 2014; Bora and Pantelis, 2015; Ahern and Semkovska, 2017; Riddle et al. , 2017; Semkovska et al. , 2019; Van Rheenen et al. , 2019). In contrast, dementia can frequently be accompanied by depression, hallucinations, delusions, and anxiety (Lyketsos et al. , 2002; Di Iulio et al. , 2010). Both neurodegenerative and psychiatric diseases often present themselves with symptoms normally attributed to the other entity before their ‘classic features’ appear (Lyketsos et al. , 2002; Reichenberg, 2010; Eikelboom et al. , 2021). We will later elaborate on the overlapping presentation in the definition paragraph. However, for these questions to be answered, one needs insight into the causal entities’ or aetiology behind the complaint: the qualitative part . In addition to the ‘quantitative’ and ‘qualitative’ reasons for knowing the cognitive function of a patient in old age psychiatry, there are other reasons for cognitive screening. As mentioned above, the prevalence of MCI and dementia above 60 years of age is high in the general population, and this will be even higher in an older psychiatric setting. The population of older people is increasing owing to demographic factors. This eventually results in more older patients having psychiatric problems. This, in turn, will increase the number of psychiatric patients with cognitive complaints in addition to the expected increase in patients with neurodegenerative disorders. This will lead to an increase in referrals to older psychiatric clinics for patients with cognitive impairment. Together with more awareness due to public campaigns on cognitive impairment, there is also a trend of being assessed earlier in the process with fewer complaints (Grimmer et al. , 2015). Some of themhad only subjective complaints without being able to objectify these complaints. Even

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