The precise origins of mental illness are still largely a mystery to us, despite the abundance of knowledge we’ve acquired over the past century. We’ve come a long way, but no one knows for sure what causes certain mental illnesses, or why they occur in certain people or at certain times. We have, however, come across compelling evidence that mental disorders are not contagious, or able to be transmitted through contact.

Though it may be impossible to transmit mental illness through a cough or sneeze, emotions and mental symptoms can sometimes be more complicated than a viral pathogen when it comes to transmission. We do know that emotions can be influenced by those of the people around them and that some specific symptoms of mental disorders (ie: binge eating) can sometimes spread among peers. These phenomena could cause beliefs about transmission that have little to no scientific backing.

The way we think about a mental illness may have a big effect on the way we interact with those suffering from them. If people hold unfounded beliefs that mental illness is contagious, how does that affect interaction with those diagnosed with the disorder?

A new paper by Professor Jessecae Marsh and Lindzi Shanks, published in the journal of Memory & Cognition, suggests that the belief a person holds about psychiatric disorders can influence their interactions with those diagnosed with them. In a series of several experiments, the researchers found that the public may still hold some not-so-scientific beliefs about mental illness.

In the first study, Marsh and Shanks had participants rate 12 different mental disorders on how likely they thought it would be for someone to catch the illness through close contact with a person who had it. The ratings ranged from zero to 100 percent probability, and the ratings ended up varied across the disorders.

Alcohol abuse, for example, was rated as 56 percent likely to be transmitted, anorexia came in at 35.7 percent, and depressive disorder was rated at 32.2 percent. The illnesses ranked as the least likely to be transmitted were Tourette’s disorder (4.2 percent), autism (5.3 percent), and schizophrenia, with 7.4 percent.

The participants then answered questions about how willing they would be to interact with a person with each disorder. They would be asked to rate their agreement with statements like “I would be willing to work with someone with anorexia,” or “I think someone with schizophrenia is dangerous.”

In general, the researchers found that people’s willingness to interact with a person with a given mental illness was best predicted by their belief about the communicability of that disorder. Other beliefs played a much smaller role. This led researchers to ask a follow-up question: How did people think the transmission of mental illness from person to person actually occurred?

A second study revealed that participants seemed to believe diseases like the flu or chicken pox were transmitted through physical contact during a relatively short timescale (ie: sneezing on someone). When it came to mental illnesses, though, people seemed to believe that social interactions were responsible for transmission of the disease and on a much longer timescale.

Somewhat unsurprisingly, study subjects were rather vague when asked how exactly they believed transmission occurred. One participant said they thought anxiety disorder could be transmitted because “the person’s anxiety will rub off.” Another explained that for alcohol abuse, “If you hang out with someone that drinks all the time, you will soon be drinking a lot as well.”

Those suffering from mental illness face many challenges, often including social isolation and stigma. The study identifies one major source that may contribute to these issues: belief that mental illness is transferred from one person to another. These beliefs are almost absolutely false, but education and knowledge will hopefully come to override false concerns.

Source: Marsh J, Shanks L. Thinking you can catch mental illness: How beliefs about membership attainment and category structure influence interactions with mental health category members. Memory & Cognition. 2015.