1 23 Social Psychiatry and Psychiatric Epidemiology The International Journal for Research in Social and Genetic Epidemiology and Mental Health Services ISSN 0933-7954 Volume 47 Number 8 Soc Psychiatry Psychiatr Epidemiol (2012) 47:1243-1250 DOI 10.1007/s00127-011-0431-3 The age at onset of psychosis and tobacco use: a systematic meta-analysis Nicholas Myles, Hannah Newall, Michael T. Compton, Jackie Curtis, Olav Nielssen & Matthew Large