Disorders affecting the brain cover a wide spectrum of conditions and many increase in incidence and prevalence with older age. Their symptoms are variable affecting each individual person differently, with some diseases following a progressive pattern. In these instances, as progression occurs, symptoms may impact on family and friends, as well as having a significant effect on the health and wellbeing of those affected. This article, the first in a two-part series, looks at dementia and strokes and the various types of these two conditions. A brief insight into the signs and symptoms, diagnosis, treatment and management and long-term outlook is discussed to improve knowledge and confidence among general practice nurses (GPNs) and non-medical prescribers when caring for patients and their families affected by these devastating diseases.