When people learn they are predisposed to Alzheimer's disease, any depression or anxiety is not long lasting, a new study said.

A team led by a University of Michigan researcher tested 162 people with a parent who has Alzheimer's disease, which meant that the subjects' risk was higher than the general population. They were also given genetic counseling and offered testing for a gene known as APOE, which increases the risk another 50 percent, according to a news release.

Those who had the test were followed for more than a year to determine the impact of the information.

Scott Roberts, who co-authored the study, said the work was meant to address the debate about how much harm knowing one's risk can cause.

The researchers measured anxiety, depression and test-related distress. Test-related distress increased slightly at six weeks for people with the risk-increasing form of the gene, but not at 6 months or one year, Roberts said. Anxiety and depression levels remained stable.

"Some people might say, 'I'm thinking about this a lot,' but it didn't translate into long-term depression or anxiety," Roberts said. "The findings show if you do (disclose this genetic information) genetic counseling may be an important component to ensure that most people do not respond with significant distress."

That included, for example, making sure people understood that a 55 percent chance of getting the disease means there's a 45 percent chance of not getting it.

Twenty percent of the people decided not to learn their risk factor before being tested, he said.

The study appears in the New England Journal of Medicine.