[1] Kings Coll London, Inst Psychiat Psychol & Neurosci, Dept Basic & Clin Neurosci, 125 Coldharbour Lane, London SE5 9NU, England
[2] Kings Coll London, MRC Ctr Neurodev Disorders, London, England
[3] Kings Coll Hosp London, London, England
[4] Evelina London Childrens Hosp, London, England
[5] Vestre Viken Hosp Trust, Drammen Hosp, Dept Neurol, Drammen, Norway
[6] Univ Oslo, Inst Clin Med, Oslo, Norway