Historically, since the 1980s, schizophrenia has been diagnosed more frequently in men compared to women, whereas before this time there had been no significant differences. This is an example of alpha bias, according to Cotton et al, because women are more likely to be able to continue working, maintain good interpersonal relationships and show less distress than men. This means that the schizophrenic symptoms of women may be masked or not severe enough to merit a diagnosis