Some patients are too emotional to remember what a doctors tells them, researchers suggest.
People do not always take in what a doctor tells them
Psychologists from the University of Marburg, Germany, tested how people perceived medical consultations.
People who were worried about their health were frequently reluctant to believe their condition was unlikely to have a medical origin.
The Publish Library of Science Medicine report suggests doctors should check patients do take information on board.
When people have minor symptoms, such as headaches or stomach aches, most are happy if a doctor assures them there is no reason to worry.
But some have a long history of worrying, and keep returning to the doctor seeking a diagnosis.
The patients in this study visited doctors on average 32 times per year, contributing significantly to medical expenses and workload on medical staff.
The German researchers suspected the patients might misinterpret medical explanations.
Breakdowns and barbecues
They asked them to listen to three taped conservations, which were also played to healthy people and other patients with depression.
One of the tapes involved a doctor explaining test results to a patient with abdominal pain, while the second involved a negative conversation about the lack of an invitation to a barbecue, while the third was a neutral exchange about a car breakdown.
Each of the exchanges had a range of responses; four which offered possible explanations - two which were definitively negative, such as "the reason for your complaint is definitely not gastric flu", and two which were ambiguous, such as "it is unlikely you have cancer".
People were then asked about their memories of the explanations offered for each scenario.
In the test result scenario, even when it was clearly explained that there was no medical cause for the patient's complaint, "emotional" patients were less likely to take on board what they had been told by the doctor.
But they did not respond as emotionally when they listened to the other conversions.
The researchers, led by Dr Winifred Rief, said people who had such responses could have had difficult experiences with doctors.
To make sure patients accurately remember a consultation, Dr Rief and her colleagues suggest doctors ask patients to summarise what they are told to double-check they understand the medical explanation correctly.
Writing in PLOS Medicine, they say: "This would make it possible to detect when patients have misremembered the likelihood of various medical explanations, and provide an opportunity to correct the situation.
"This would benefit patients and reduce the strain on health care systems."
Dr Simon Fradd, a GP and spokesman for the UK organisation Developing Patient Partnerships, said: "When a GP is uncertain of the specific problem it is not entirely surprising that the patient experiences uncertainty and may latch on to something that is frightening or worrying.
"GPs obviously need to be aware of that in these types of situations and try go offer reassurance."