Grouping of behavioural and psychological symptoms of dementia

Abstract

Objective: A wide range of behavioural and psychological symptoms (BPSD) are common in dementia, and it has been suggested that groups of correlated symptoms should be studied together. Here, we describe the groups of BPSD that have been identified in the literature and how they have been used to study associations, burden, treatment and underlying biology.

Methods: The literature database PubMed was searched for articles that identified clusters or factors of BPSD or used previously defined symptom groups.

Results: Sixty-two studies were included. Generally, the following symptom groups were suggested: affective symptoms, including depression and anxiety; psychosis, including delusions and hallucinations; hyperactivity, including irritability and aggression; and euphoria. Symptoms that did not show consistent results include apathy, eating disturbances, night-time behaviour disturbances, disinhibition and aberrant motor behaviour. Symptom groups differed in their associations, treatment and biology.

Conclusions: Studies investigating symptom groups show relatively consistent results. Studying symptom groups allows similar symptoms to be studied together, which might strengthen results and may point to differences in their aetiology and treatment. However, a large amount of the individual variability of the symptoms could not be explained by the factors, and authors should carefully address their research question and hypotheses to decide if symptoms should be studied in groups or individually. Clinicians need to consider each symptom in its own right and also to be aware of the interrelations between them when assessing patients and developing strategies for treatment.

Keywords: behavioural and psychological symptoms of dementia; cluster analysis; dementia; factor analysis.

Figure 1

Number of times individual symptoms have been included in the symptoms groups affective symptoms (red), psychosis (blue), hyperactivity (green), euphoria (orange) or other (purple), as identified by n = 29* studies using the Neuropsychiatric Inventory. For example, a factor of affective symptoms (red) was identified by n = 28 studies; depressive symptoms were included in this factor by all but one of the studies, anxiety by n = 25 and apathy by n = 15. Other symptoms such as hallucinations, irritability, sleep problems and wandering were included in this symptom group by some. Although anxiety was most often included in the affective symptoms group, six studies found it was associated with symptoms of hyperactivity (green). Full details of the study design and results of each of the studies are included in Additional File 3. Factor loadings of 0.40 or above are included. Symptoms can load on more than one factor. Symptom groups are defined on the basis of those factors most often reported by the studies. When factors include symptoms from more than one of the defined groups, the factor is mapped to the group with which it shares the highest number of symptoms and/or symptoms with the highest factor loading. When two or more ‘other’ factors were identified, both are included in the ‘other’ group. *Studies using cluster analysis or latent class analysis are not included. For studies reporting both explanatory factor analysis and confirmatory factor analysis, only confirmatory factor analysis is included. Zuidema et al. (2007) report on three subgroups that are included separately. Vilalta-Franch et al. (2010) reports on the same sample as Garre-Olmo et al. (2010a, 2010b) and is excluded from the figure. The sample included (Dechamps et al., 2008) overlaps with Prado-Jean et al. 2010 and is excluded from the figure. Germain et al. , Petrovic et al. 2007 and Aalten et al. all report on European Alzheimer's Disease Consortium (EADC) data; only Aalten et al. is included in the figure. When a study reports on several different samples (including Truzzi et al. and Zuidema et al., 2007), results are reported separately for each sample. **Included in NPI-12 only. Del, delusions; Hal, hallucinations; Agg, agitation/aggression; Dys, dysphoria; Anx, anxiety; Eu, euphoria; Apa, apathy; Dis, disinhibition; Irr, irritability/lability; Abe, aberrant motor behaviour; Sle, night-time behaviour disturbances; Eat, appetite and eating disturbances.