The impact of consanguinity on risk of schizophrenia.

The cross-sectional study was based on the Primary Health Care Centers among Arab patients aged 18–55 years from January 2009 to December 2010. Of the sample size of 1,491 subjects, 1,184 patients agreed to participate in this study (79.4%). Institutional review board approval was obtained from the Hamad Medical Corporation for conducting this research. The subjects who did not agree to participate (20.6%) were demographically similar to those who had agreed to participate. A validated self-administered questionnaire was designed to collect the data based on face-to-face interviews by physicians and qualified nurses. Following completion of this questionnaire by the patient, the provisional diagnosis score was calculated from the responses, which was then confirmed by psychiatrists through a clinical questioning using DSM-IV criteria. The general diagnostic screening questionnaire was not designed to make a definitive diagnosis but rather to identify people at high risk. Content validity, face validity and reliability of the questionnaire were tested using 50 paSchizophrenia (Sz) occurs worldwide and is one of the severest mental disorders [1] . The World Health Organization documented that Sz has been recognized as a major public health problem in the fourth position among the global burden of diseases [2] . It has been generally accepted that Sz, like all other complex diseases, is caused by genetic and environmental factors. Bener et al. [3] reported that consanguinity (inbreeding) may be associated with an increased risk for a wide range of genetically complex disorders. Marriages between relatives are common worldwide and lead to human consanguinity. It was found that consanguineous marriages increase the risk for Sz in offspring [4] . Since consanguinity is widely practiced in the Eastern Mediterranean region, it was considered worthwhile to study this aspect in this population. Moreover, an elevated parental consanguinity rate of 52% was reported in the State of Qatar [3] . The aim of the study was to examine the impact of consanguinity on the risk for Sz disorders and investigate the inbreeding characteristics of the Sz patients. Received: May 25, 2011 Accepted after revision: April 8, 2012 Published online: August 7, 2012