Stereotype threat is the feeling that one is the target of demeaning stereotypes and has been found to affect performance among a number of different people doing a number of different tasks. Interestingly people do not have to actually be treated in a negative way for this effect to occur, they just have to believe they are being stereotyped. People with schizophrenia are often thought to have poor social skills and a team of researchers from the University of New South Wales and the University of Queensland wondered whether this could be due to stereotype threat. They got 30 people with schizophrenia to talk to two 'confederates.' The people with schizophrenia were told that one of the confederates knew about their diagnosis while the other didn't; but in fact neither of the confederates knew that they were talking to someone with schizophrenia. Although the participants with schizophrenia did not perceive any differences in their own social behaviour those confederates who talked to someone who thought the confederates knew about their mental-health problems rated the participants' social skills as poorer.
Henry, Julie D., von Hippel, Courtney and Shapiro, Lisa - Stereotype threat contributes to social difficulties in people with schizophrenia British Journal of Clinical Psychology March 2010, 49(1), 31-41