Recognition of the additional social handicaps and distress that people with mental illnesses experience as a result of prejudice. To determine opinions of the British adult population concerning those with mental illnesses as baseline data for a campaign to combat stigmatization. Survey of adults (n = 1737 interviewed; 65% response) regarding seven types of common mental disorders. Responses evaluated concerned eight specified perceptions. Respondents commonly perceived people with schizophrenia, alcoholism and drug addiction as unpredictable and dangerous. The two latter conditions were also viewed as self-inflicted. People with any of the seven disorders were perceived as hard to talk with. Opinions about effects of treatment and prognosis suggested reasonable knowledge. About half the respondents reported knowing someone with a mental illness. Negative opinions indiscriminately overemphasize social handicaps that can accompany mental disorders. They contribute to social isolation, distress and difficulties in employment faced by sufferers. A campaign against stigma should take account of the differences in opinions about the seven disorders studied.