Schizophrenia linked to verbal issues

DURHAM, N.C., Jan. 25 (UPI) -- U.S. researchers say they have linked a pattern of child cognitive difficulties to schizophrenia.

Researchers at Duke University in Durham, N.C., tracked development of adults who had been diagnosed with schizophrenia, and found a pattern of childhood cognitive difficulties.

The study, published in the American Journal of Psychiatry, used data from the Dunedin Multidisciplinary Health and Development Study -- a long-term study of more than 1,000 New Zealanders -- and looked back at cognitive tests taken at ages 3, 5, 7, 9, 11 and 13.

"The proportion of kids who don't score well on these tests is big, and the number of kids who develop schizophrenia is tiny," study co-author Terrie Moffitt says in a statement. "We looked backwards to understand more about how schizophrenia may develop."

The researchers found adults with schizophrenia had early deficits in verbal and visual learning, reasoning and conceptualization that remained with them as they grew. They also showed slower development than their peers in processing speed, attention, visual-spatial problem-solving and working memory.

The study findings challenge a theory schizophrenia stems from a deterioration of cognitive abilities.