Depression often occurs in older adults due to a poor sense of smell

Depression often occurs in older adults due to a poor sense of smell. A study conducted over eight years on over 2,000 older adult. Living in the community, they found strong evidence linking a weaker sense of smell with a higher risk of depression.

Occurs in a June 26 study: Losing the ability to smell doesn’t directly cause depression but signals poor overall health and well-being.

They have noticed many times that having a weak sense of smell can be an early sign of neurodegenerative diseases like Alzheimer’s disease and Parkinson’s disease. It can also make it more likely that you will die. “This research highlights the connection it has with feelings of sadness.” Explains Vidya Kamath, Ph.D., a professor in psychiatry and behavioral sciences at Johns Hopkins University School of Medicine. Also, this study looks at things that might affect how smelling things and feeling sad are related, such as problems with thinking and inflammation.

The research looked at information collected from 2,125 people. They took part in a government study called the Health, Aging, and Body Composition Study (Health ABC). This group of healthy older adults, aged 70–73 in 1997–98, participated in an eight-year study. The people in the study had no problems walking a short distance, climbing a few steps, or doing everyday tasks when the study began. They were evaluated in person once a year and over the phone every six months. The tests checked if people could smell certain things, if they were feeling sad, and how well they could move around.

Occurs in Research and Discoveries on Depression in Older Adults

In 1999, when they first checked smell, 48% of people had a normal sense of smell, 28% had a weaker sense of smell known as hyposmia, and 24% had lost their sense of smell completely, known as anosmia. People who could smell things well were usually younger than people who had trouble smelling or couldn’t smell at all. During the follow-up period, 25% of the participants experienced significant signs of depression. When researchers studied this more, they found that people who couldn’t smell well or had lost their sense of smell were more likely to become depressed over time compared to those who had a normal sense of smell. People who could smell well were usually younger than those who had trouble smelling or couldn’t smell as well.

In the study, researchers observed three patterns of depressive symptoms among the group: consistently low, consistently medium, and consistently high levels. Occurs with a weaker sense of smell is a higher chance of experiencing moderate or high depression. This means that the worse someone’s sense of smell, the more likely they are to experience depressive symptoms. These findings remain consistent even after considering age, income, lifestyle, and use of antidepressants.

Losing the ability to smell can occur, affecting health and behavior in various ways. It can make it harder to detect harmful food or gas and diminish the enjoyment of eating. According to Kamath, this loss may also indicate a significant underlying health issue. Smelling is a crucial way to connect with our surroundings, and this study suggests it could signal a risk of developing depression later in life.

Humans have a sense of smell that is controlled by chemicals.

Humans have a sense of smell that is controlled by chemicals. It works using special cells called olfactory neurons in the nose. These special cells have a scent detector. It detects the tiny particles released by things in the environment and sends them to the brain for understanding. The more smell molecules there are, the stronger the smell. Combining different molecules leads to different smells.

Smells are handled by the brain’s olfactory bulb. This part of the brain works closely with other structures like the amygdala and hippocampus. These structures help with remembering things, making decisions, and feeling emotions.

Occurs in Johns Hopkins University research: Evidence suggests a link between smell and depression. Biological factors, including changes in serotonin levels and brain volume, as well as behavioral factors like reduced social function and appetite, might explain this connection.

Conclusion

The researchers want to do the same study again with more groups of older adults. They also want to see if the part of the brain called the olfactory bulb is different in people with depression. They also want to see if using smell can help prevent late-life depression.

Other scientists who helped with this research are Kening Jiang, Danielle Powell, Frank Lin, and Jennifer Deal from the Johns Hopkins University School of Medicine and Bloomberg School of Public Health. Kevin Manning from the University of Connecticut also contributed. 

Occurs According to Johns Hopkins University School of Medicine policies: The authors had no conflicts of interest. This research, funded by NIH and its institutes, reported no conflicts of interest in its findings.