Scientists are working hard to discover the genetic factors that lead to development of schizophrenia. The December, 2007, issue of The Archives of General Psychiatry reports new evidence of connections between the genes controlling schizophrenia and IQ. People with schizophrenia often have impaired working memory and lower IQ. This complex study involved pairs of identical and fraternal twins in the UK, of which one, both, or none of the twins had schizophrenia. Researchers found that healthy identical twins shared cognitive impairments with their ill twin more often than fraternal twins did with theirs. They found that 92% of the correlation between IQ and schizophrenia was explained by shared genetic variability. Findings like this may one day, far in the future, help researchers identify specific genes that can be targeted by genetic therapies.