People who fake symptoms of mental illness can convince themselves that they genuinely have those symptoms, a new study suggests. People will also adopt and justify signs of illness that they never reported themselves when presented with manipulated answers, according to the study published online July 9 in the Journal of Clinical and Experimental Neuropsychology. Not only do the findings demonstrate that deliberately feigning illness can evolve into an unconscious embellishment of symptoms, they indicate that self-perception of mental health is susceptible to suggestion. The study has particularly serious implications for cases in which people fake mental illness to take advantage of the legal system.
"This study shows a couple ways people come to believe they have troubles they wouldn't otherwise endorse," says Elizabeth Loftus, a psychologist at the University of California, Irvine, renowned for her research on misinformation and false memories. "One way is to give them misinformation about what they reported before, but this study shows yet another kind of suggestion, which is to induce people to, in essence, lie. And it leaves them with a residual effect to keep doing so. Once you get people to report a particular symptom, like 'I have a little trouble concentrating,' even if they would never say that on their own, you turn them into someone who later on says they do have trouble concentrating."
In the new study psychologist Harald Merckelbach and colleagues at Maastricht University in the Netherlands first asked 31 undergraduates to read a story about a criminal defendant who had trespassed on a medieval building, dislodged some stones that fatally wounded a young girl, and received a charge of manslaughter. The experimenters told all participants to pretend they were the defendant in the story and complete a 75-item true-or-false self-report survey of mental health called the Structured Inventory of Malingered Symptomatology (SIMS). The SIMS includes "very bizarre and extreme symptoms that most real patients would not endorse," Merckelbach says, such as hearing ever-present voices or the sensation of 1,000-kilogram weights attached to one's legs. The researchers asked one subset of the subjects to fill out the survey honestly, instructing the rest to exaggerate their symptoms in hopes of feigning a mental illness and minimizing criminal responsibility.
Once the undergraduates had completed the survey, they were asked to spend an hour on games and tasks like sudoku puzzles before completing the SIMS once again. This time, the researchers instructed both subgroups to fill out the survey honestly (although still playing the role of defendant): participants who had feigned illness were told that they had been detected as fakers and needed to complete the survey with truthful answers; the other group was told that sometimes people change their minds about their symptoms and so they should fill out the SIMS again. The group that initially reported their symptoms honestly hardly changed their answers. But the mental illness pretenders continued to exaggerate their symptoms, despite the request for sincerity.