Longitudinal course of behavioural and emotional problems of young persons with Prader-Willi, Fragile X, Williams and Down syndromes

We present a comparison of levels of emotional and behavioural disturbance in children and adolescents with four genetically determined causes of intellectual disability (ID) and a control group of epidemiologically derived young people with ID as a consequence of a range of known and unknown causes. The behavioural and emotional disturbances were reassessed 4 years later providing one of the few follow-up studies of these genetic disorders. The study shows that genetic cause of ID has a strong influence on the severity of behaviour problems. Persons with Down syndrome have significantly less behaviour disturbance than controls, and young persons with Prader-Willi or Williams syndrome have significantly more disturbance than controls. These patterns persist over time, although there are non-specific trends for the level of disturbance to improve or worsen in particular syndromes.