With the long term goal of intervening to promote better physical and psychosocial functioning of children in South Africa, this study will determine how the ability of children with neurodevelopmental disorders to function cognitively and socially is influenced by both health-related (HIV, anemia, other infection), contextual (socio-economic and environmental, access to care and therapeutic intervention) and psychosocial factors (caregiver characteristics including mental health and substance use, family functioning). Approximately 2000 5 and 6 year old children from a HIV prevalent area will be screened for disability and then assessed before school entry. They will be reassessed 24 months later after school entry. The study will offer HIV testing to children and caregivers and referral for treatment for all conditions identified. Many of these children live with parents who are ill or have parents who have died from AIDS. Additional challenges such as poverty, inadequate access to health care and to education are common;many other risks to child health and well-being, including inadequate nutrition, infection and trauma as well as caregiver depression and substance use affect many children. As a result, many children do not function at optimal levels, and are at risk for developmental disabilities. The study will investigate first cross sectionally and then longitudinally the relationships among neurodevelopmental disorders and the above mentioned risk factors including as outcomes, child cognitive and psychosocial functioning and in the longitudinal aim, school functioning .The study will address both cross sectional and longitudinal relationships, assessing the impact of referral, treatment and access to programs over time. Community ethnographic studies will be linked to the findings of the epidemiologic study to identify culturally appropriate interventions. We will identify factors open to intervention which are known to affect child risk and resilience and work with community leaders in a participatory approach to develop an effective community based intervention. In addition, training in research methods and enhancing research capacity will be one of the key aims of this research. This will involve training public health students, ethnography students, pediatric registrars, allied health professionals and community health workers in both field and classroom teaching and training. This will be managed in collaboration with the UKZN Fogarty Program, the Valley Trust, the Rehabilitation Unit and the Medical School at UKZN with assistance from the Columbia investigators