Do you feel like you know why you’re here?

The answer to that question could determine how you feel day-to-day.

If you’ve found meaning in your life, you’re more likely to be both physically and mentally healthy, a new study reports.

On the other hand, people restlessly searching for meaning in their life are more likely to have worse mental well-being, with their struggle to find purpose negatively affecting their mood, social relationships, psychological health, and ability to think and reason.

“We found presence of meaning was associated with better physical functioning and better mental functioning,” said senior study author Dr. Dilip Jeste. He is senior associate dean for the Center for Healthy Aging at the University of California, San Diego, School of Medicine.

“Many think about the meaning and purpose in life from a philosophical perspective, but meaning in life is associated with better health, wellness and perhaps longevity,” Jeste continued. “Those with meaning in life are happier and healthier than those without it.”

This conclusion comes from a three-year study of more than 1,000 people aged 21 and older living in San Diego County.

All participants were asked to fill out a battery of questionnaires that assessed their physical and mental health, as well as how sharp their brains function.

They also filled out a questionnaire aimed at determining the amount of meaning they’d found in life, as well as their continued search for meaning.

Meaning in life is a very individualized concept, Jeste said. It could be drawn from your faith or from your family, from your work or your community service, or your role in society.

Jeste and his colleagues found that as people get older, they tend to follow along a U-shaped curve in their search for meaning in life.

The search for meaning is high in young adulthood, as people make decisions about career and education and family that will shape the rest of their lives, the study reports.

“That’s a period of considerable anxiety. You are desperately searching for meaning, but you haven’t found it,” Jeste said of people in their 20s.

As people grow older and settle into their lives, they are more and more likely to discover the things that give their lives meaning, the researchers found.

But then, as people enter their old age, the search for life’s meaning again starts to roil within them, results show.

Physical and mental infirmity challenges their notion of themselves, and the increasingly frequent deaths of family and friends force them to contend with grief and their own mortality, Jeste said.

“They start questioning the meaning that they’d found in life at an earlier age, and they start searching again,” Jeste said. “The purpose at 75 cannot be the same as that at 35.”

These big questions — and whether you’re still looking for the answers, at whatever age — are associated with your personal health, results show.

Contentment with life was associated with better physical and mental health, while a continuing search for meaning was associated with poorer mental health and less effective brain function, the study showed.

You could imagine that a doctor finds meaning in their life because they help people who are suffering, and that provides them with satisfaction and a solid base for happiness, said Dr. Philip Muskin, a professor of psychiatry with the Columbia University Medical Center, in New York City.

On the other hand, a doctor suffering from burnout who questions whether they’re really helping others isn’t going to be either happy or healthy.

“If you are still searching for meaning as a physician, that is likely to make you unhappy,” Muskin said. “Not necessarily depressed, but if you are still searching for meaning that is likely to make you uncomfortable in life.”

So what can you do to provide yourself with a firmer understanding of your life’s purpose?

Jeste suggests that the Serenity Prayer provides one blueprint — accepting the things in life you can’t change while working to improve the things you can.

“You can find the things that you can do that make you happy and that are useful to others,” Jeste said. “By doing that, you create your own value to society.”

Thoughtful conversation also can help, Muskin said, either with your friends or your family, or a religious figure or a therapist.

“Ask yourself the hard question. What is it I want to get out of this?” Muskin said. “Meaning comes from many different sources, and if you truly feel you don’t have meaning, you should sit with someone and have that conversation. What are we doing?”

Middle-aged people can help maintain the meaning they’ve found in life by making solid plans for what they will do in retirement, Muskin added.

“I see this all the time in my practice — people who retire into nothing,” Muskin said. “They have made no plans. They were professionals for years and decided to retire and their lives are empty. Now they’re searching for meaning in life because what they did and who they were never much separated.”

The new study was published online Dec. 10 in the Journal of Clinical Psychiatry.