Samenvatting

What is already known about depression in dementia? Comorbid depression in people with dementia is associated with decreased quality of life (Shin et al., 2005), greater health care utilization (Kunik et al., 2003), higher mortality rates (Suh et al., 2005) and decreased caregiver’s wellbeing (Kerkstra et al., 1999; Shin et al., 2005). Little is known about the etiology of depression in dementia. It is thought to be partly caused by neurological changes due to the dementia and partly by psychological reactions to the presence of the dementia (Janzing and Zitman, 2002).
The prevalence rates for significant depressive symptomatology in dementia in previous studies range from 15 percent (Vida et al., 1994) to as high as 50 percent (Migliorelli et al., 1995). Recognition of depression in dementia is a complex task for caregivers and, as a consequence, under‐recognition is high (Olin et al., 2002b). This is partly caused by an overlap of some of the symptoms of dementia with prominent symptoms of depression (e.g. apathy). Moreover, people with dementia have severe difficulty in expressing themselves, especially in the latter stages of dementia. In addition, the assessment of depression in people with dementia is complex, since in this population the syndrome is qualitatively different from depression in non‐demented elderly populations as diagnosed with DSM‐IV criteria for Major and Minor Depression (DSM‐IV: APA, 1994) (Olin et al., 2002b).
In 2002 an expert group from the American National Institute of Mental Health (NIMH) therefore developed specific criteria for depression in Alzheimer Disease, the most frequent type of dementia. These are the ‘Provisional Diagnostic Criteria for Depression of Alzheimer Disease’ (PDC‐ dAD) (Olin et al., 2002a). Depression of Alzheimer Disease is assumed to be different from DSM‐IV Major Depressive Disorder with respect to the type and intensity of its symptoms. As compared with DMS‐IV criteria for Major Depressive Disorder, specific symptoms for depression in Alzheimer Disease are ‘irritability’ and ‘social isolation/withdrawal’. Another important difference compared to DSM‐IV criteria is that in Depression of Alzheimer Disease the presence of at least three, instead of five, symptoms is required, and symptoms are not required to be present nearly every day. Using the PDC‐dAD criteria should improve recognition of Depression of Alzheimer Disease. Two recent studies in demented outpatient populations showed that with the Provisional Diagnostic Criteria for Depression of Alzheimer Disease higher rates of depression were indeed identified than with DSM‐IV or ICD‐10 criteria for Major Depression (Vilalta‐Franch et al., 2006; Teng et al., 2008). To our knowledge, the criteria have not been previously applied to a demented inpatient population, such as psychogeriatric nursing home residents.