In a study published in Memory and Cognition, Jessecae Marsh and Lindzi Shanks found that people believe that mental health disorders may be transmitted via social contact, and that these beliefs affected willingness to interact with people suffering from a mental illness. In the first stage of the study, the researchers asked participants to rate the probability of contracting various illnesses through close contact on a scale of 0-100%. The perceived likelihood of transmission was highest for alcohol abuse (56%), anorexia (35.7%), and major depressive disorder (32.2%), while Tourette’s disorder, autism, schizophrenia, and bipolar disorder ranked lowest (4.2%, 5.3%, 7.4%, and 11.2% respectively). In the second phase, participants were asked questions about their willingness to have contact with people suffering from various disorders:
People’s willingness to interact with someone with a given disorder was best predicted by their belief about the communicability of that disorder, with other beliefs—about, for instance, the disorder’s psychological basis and the extent to which an individual can control the symptoms she displays—playing a much smaller role. A second experiment helped establish that this predictive relationship was actually causal: It was indeed beliefs about communicability that caused different attitudes toward personal interaction.
In other words, participants’ willingness to interact with a person depended primarily on their perceived likelihood of catching the illness, increasing the isolation of those who suffer from the most “contagious” mental health disorders.