Children and adolescents of both genders aged 7-18 years inclusive at the beginning of trial. Children over 16 should be in full-time education and not expected to leave school within 6 months. Additionally children over 16 will be assessed for their capacity to give consent to participate in the trial using the Mental Capacity Tool (Children over 16 appendix). This tool was designed for use with young adults with intellectual disability, neurodevelopmental or other disorders that might impair their ability to give informed consent. Evidence of potential impairment in capacity includes the diagnosis of learning disability, IQ <70, significant deficity in adaptive functioning, or other signs or symptoms of mental disorder that might compromise capacity to give informed consent. The assessment establishes understanding, retention of information, use of information to make the decision and communication of the decision. These reflect the limbs of the 'capacity test' as defined in the Mental Capacity Act 2005. We expect that the majority of the over 16 children would have difficulties in showing the necessary understanding in order to consent due to their special needs; in these cases a consultee will be appointed following the procedure described in the Children over 16 appendix.

1) To change the period off-psychotropic medication from 3 months to 1 month in order for the children to have quicker access to the trial. 2) To clarify that children who ·use to be stimulants should be off them for at least a week.