Abstract
This study examined neuropsychological functioning at age 13 in individuals who later developed schizophrenia spectrum disorder. Participants were members of the Dunedin Multidisciplinary Health and Development Study, an unselected birth cohort study. Study members who were diagnosed as having schizophrenia spectrum disorder at age 26 were compared with healthy controls and also with groups diagnosed as having had a manic episode or nonpsychotic depression /anxiety disorders at age 26 on their performance on neuropsychological tests at age 13. Attentional/ executive and motor impairments at age 13 were found in Study members who later fulfilled diagnostic criteria for schizophrenia spectrum disorders but not other psychiatric outcomes, suggesting that these are the earliest-emerging neuropsychological deficits in schizophrenia-related disorders.