This is a two-stage design to conduct screening for mental disorders including autism and all neuropsychological studies in addition to questionnaires. Moreover, clinical assessment will be conducted among urban students (n = 3000) and rural students (n = 1500) from a three-stage cluster sampling. All the screen positive (estimated n = 900) and 10% of screen negative (estimated n = 360) will receive the full diagnostic interview (K-SADS-E to obtain the pregnancy, developmental and medical history. For students who leave of absence, we will visit them at home to complete all the assessments.