Many people who discover that they have inherited a higher risk of developing Alzheimer’s can cope with the news, especially if they receive the it through genetic counseling: they may experience depression or anxiety at first, but it does not last long, according to a new study from the US.
The study was the work of co-author Scott Roberts, now a researcher at the University of Michigan School of Public Health in Ann Arbor, and colleagues, and is published in the New England Journal of Medicine, NEJM.
Roberts did the research while he was at Boston University. He is also co-principal investigator on the Risk Evaluation and Education for Alzheimer’s Disease (REVEAL) study, a series of randomized clinical trials that are looking at the impact of a genetic susceptibility testing program for adult children of people with Alzheimer’s.
The NEJM study addresses a debate that has been going on for some time, about whether being told they have an inherited predisposition to Alzheimer’s disease causes psychological harm to people, especially if there is a history of it in the family.
People with a family history of Alzheimer’s disease are already at higher risk. But the risk is even higher if they also carry a certain variant of the APOE gene (Apolipoprotein E).
Having a parent with Alzheimer’s is thought to increase one’s risk of developing the disease by age 85 to between 30 and 35 per cent, compared with a general population risk of 10 to 15 per cent, said the authors. If you also carry the APOE variant the risk is 50 per cent.
For the study Roberts and colleagues recruited 162 participants with at least one parent who had been diagnosed with Alzheimer’s disease.
The participants first took part in an education session about Alzheimer’s and were then offered a genetic test that looked for presence of the APOE variant that conferred higher risk of Alzheimer’s.
The participants that agreed to have the test were given their results by trained genetic counselors.
The researchers then followed them for about 12 months and assessed the psychological impact of the revelation. The participants completed tests for depression, anxiety and test-related distress before disclosure, and then 6 weeks, 6 months, and 12 months after.
The results showed that for the participants who were told they had the risk-increasing gene, the test-related distress level was slightly higher at the 6 week point, but not at the 6 month or 12 month point.
Anxiety and depression levels remained stable, said Roberts, who told the press that while some people might say they were thinking a lot about the test result, “it didn’t translate into long-term depression or anxiety”.
However, the results did show that:
“Persons with high levels of emotional distress before undergoing genetic testing were more likely to have emotional difficulties after disclosure,” wrote the authors.
“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,” said Roberts.
Genetic counseling puts the test results in context and helps people understand the meaning and limits of the results, he added, citing the example of a person with a 55 per cent lifetime risk being reminded that this also meant there was a 45 per cent risk that they would not get the disease.
The study’s results are timely because as more and more private firms offer genetic testing, it raises the question of whether people should know about genetic risks outside of a clinical context.
Roberts said some might argue that it is “paternalistic” to decide for others what they can and cannot know about their own genes.
He said that after the initial education session, only 20 per cent of the participants refused to go ahead with the test, which meant the majority wanted to know.
“I think most adult children of Alzheimer’s patients would favor the right to at least have the choice,” said Roberts.
“Disclosure of APOE Genotype for Risk of Alzheimer’s Disease.”
Green, Robert C., Roberts, J. Scott, Cupples, L. Adrienne, Relkin, Norman R., Whitehouse, Peter J., Brown, Tamsen, Eckert, Susan LaRusse, Butson, Melissa, Sadovnick, A. Dessa, Quaid, Kimberly A., Chen, Clara, Cook-Deegan, Robert, Farrer, Lindsay A., the REVEAL Study Group.
Sources: Univesrity of Michigan.
Written by: Catharine Paddock, PhD