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. © 2013 The Authors. International Journal of Geriatric Psychiatry by John Wiley & Sons, Ltd.