F90-F98: Behavioural and emotional disorders with onset usually occurring in childhood and adolescence

Behavioural and emotional disorders with onset usually occurring in childhood and adolescence represent a broad range of psychological conditions that typically start during the early developmental years. These conditions are diverse and can manifest in various ways, such as disruptive, impulse-control, or attention-deficit hyperactivity disorder (ADHD), where a child struggles to focus, act impulsively, or may display excessive activity. Mood disorders like depression or bipolar disorder, where children demonstrate unusual mood swings or persistent feelings of sadness, are also common. Another widespread condition is anxiety disorder, where intense fear or worry disrupts daily functioning. Factors like genetics, brain chemistry, environmental conditions, or traumatic events may contribute to their development. The disease progression varies with type and intensity: some children may outgrow their conditions as they mature, while others may struggle with symptoms into adulthood. The disorders bring about changes in brain function, which mainly affects the nervous system and a child's behavioural responses.