A new study has found that people feel the most lonely during their late 20s, their mid-50s and their late 80s.

Three in four people involved in the study said they experienced moderate to high levels of loneliness — which is troubling because even moderate loneliness can lead to declines in physical and mental health.

The researchers, who published their study in the journal International Psychogeriatrics on Tuesday, wrote their findings “underscore major challenges for society.”

Dr. Dilip Jeste, the study’s lead author and a professor of psychiatry and neurosciences at the University of California, San Diego, said the higher levels of loneliness in people in thier late 20s and 50s surprised his team.

“The late 20s are a period of stress because of the need to make some major life-changing decisions,” he told CTV News Channel. During this time, he said people experienced changes to their jobs and where they lived.

Other major decisions included settling on a long-term partner, deciding whether to have a child or to continue school. And the stress from these decisions could increase loneliness, Jeste suggested.

“You’re also competing with peers … so you feel that you are not doing as well as you should be. That’s what makes it stressful,” he said, noting he didn’t think social media use was a primary cause of their loneliness, as other studies have suggested.

But more research was needed to pin down exactly why people felt lonely, Jeste said.

How the study worked

Researchers looked at 340 San Diego County residents between the ages of 27 and 101 and found that men and women felt equally as lonely.

Factors that influence loneliness included whether people lived alone or what their overall mental well-being was.

Jeste stressed that being lonely didn’t necessarily mean that a person was alone or socially isolated.

Instead, loneliness meant experiencing a “subjective feeling of distress.” In other words, loneliness stemmed from a person realizing the relationships they have, might not be the ones they need.

“I may have two friends but that’s all I desire and I won’t feel lonely. But on the other hand, I may have five friends but if I desire ten friends, then I’ll feel lonely,” he explained.

Getting older means seeing more parents, friend die

Jeste called the mid-50s a “time of mid-life crisis” because this was typically when people began to see their parents and friends die.

“You realize that life is finite,” he said, which contrasts a person in their 20s who may feel like they’re “going to live forever.”

He said when people are in their 50s they can “start having physical problems for the first time.” This can include being diagnosed with arthritis, high-blood pressure, diabetes and the onset of menopause.

Jeste said feelings on loneliness only get worse as people aged, which made the third peak of loneliness in the late 80s less of a surprise.

“I know loneliness increased with old age, especially after the loss of a spouse or friends,” he said.

Being wiser could decrease loneliness

The research also found that people with higher levels of wisdom would feel less lonely and vice-versa, Jeste explained to CNN.

He and his co-authors broke down the trait of wisdom into six different categories which included empathy, how they managed emotion and their ability to make quick, effective decisions.

The study suggested personality can influence how loneliness develops and how long it will last. Researchers suggested loneliness can be tweaked through changes to their behaviour through things like therapy.

“Building a wiser society may help us develop a more connected, less lonely, and happier society,” the study said. But it noted the relationship between wisdom and loneliness needs to be further examined.