Citation bias in schizophrenic smoking rates

Clinicians - and the general public - may be being misled about the rates of smoking among psychiatric patients. Professor Simon Chapman and colleagues from the University of Sydney have found that studies reporting a very high prevalence of smoking among people with schizophrenia are cited more often than studies reporting a low prevalence. This is despite the fact that a meta-analysis by the same researchers reported an average smoking prevalence among schizophrenia patients of about 62%, rather than the 80-90% figure often cited and reported in the media. The researchers found that for every 10% increase in smoking prevalence reported in a study there was a 28% increase in the likelihood of it being cited. They also found that the majority of returns to the Google search “what percent of schizophrenics smoke?” said that the answer was at least 80%. The results indicated that a citation bias existed towards higher prevalence studies, and the public, as well as health professionals, could be forgiven for believing that the prevalence of smoking in people with schizophrenia is ‘about 90%’, the researchers said. They noted that the most commonly cited paper reporting high smoking rates among schizophrenics was published in 1986, with peak citations for the paper occurring 23 years after the data was collected. Australia’s smoking rates have roughly halved during that time, they said. Australian and New Zealand Journal of Psychiatry 2009; 43:277-282...