The prevalence and intensity of neuropsychiatric symptoms (NPSs) isolated and grouped into subsyndromes are investigated in patients with dementia in primary care (PC) with the aim to determine their distribution based on stages of dementia and the relationship between them and the intensity of symptoms.

• Cross-sectional study involving patients with dementia, not institutionalized, in a PC follow-up.

• Overall, some type of NPS was present in 98.4% of the patients, with an average of five symptoms per patient.

• Apathy [69.8%], agitation [55.8%] and irritability [48.8%] were noted to be the most frequent symptoms.

• Apathy [NPI 3.2] and agitation [NPI 3.2] were the more intense NPSs.

• Hyperactivity predominated for subsyndromes [86.0%], followed by apathy [77.5%].

• Apathy was the most common isolated symptom by phase of dementia.

• The initial stages appeared to be predominated by affective symptoms and irritability, and in advanced stages, predominance of psychotic symptoms was observed.

• The mean NPI score was 24.9 and there was an increase from 15.6 for GDS 3 to 28.9 for GDS 7.

• An NPI score 7.6 points higher was recorded for patients in the most advanced stages of dementia relative to the score for mild dementia with adjustment for the other variables.

• Overall findings suggest that NPSs are highly prevalent among patients with dementia treated in PC.

• With the progression of disease, symptoms change and increase in intensity.

• Identification of these symptoms is allowed by scales such as the NPI, which may aid in more stage-appropriate management.