In 2022, almost half a million patients in Norway came into contact with the specialist health service with brain disease as a primary or secondary diagnosis (Directorate of Health, 2024a). This is equivalent to around 9% of the population. The number of patients has been rising steadily in recent years. Mental and behavioural disorders accounted for over 60% of cases, while nervous system disorders accounted for nearly 40%. The incidence of brain diseases was highest in Northern Norway and Southeastern Norway. The largest increase was observed among women under the age of 45, linked to mental and behavioural disorders in particular. Brain diseases represent a significant and increasing burden on the specialist health service, especially in relation to mental disorders.