Many people say they live happy and healthy lives when they are involved in meaningful relationships, but it's unclear how people achieve these close and caring relationships, and how such bonds promote well-being.

In a new review that experts call a "gigantic contribution" to the field, scientists examined how relationships can encourage — or thwart — personal thriving.

Relationships can help people cope with stress and adversity, and enable them to thrive as they achieve goals and cultivate talents, said Brooke Feeney, an associate professor of social psychology at Carnegie Mellon University in Pittsburgh. [5 Ways Relationships Are Good for Your Health]

"I would define a thriving person as someone who is happy, [and] pursuing and progressing toward meaningful life goals," Feeney told Live Science in an email.

Thriving people often have purpose and meaning in life, a positive regard for themselves and others, healthy physical and mental health, and deep meaningful human connections, she added.

Parents, partners, friends and mentors can help people thrive. The type of support needed, however, varies depending on whether or not the person is facing a setback, such as losing a job or going through a divorce.

Hard times

During times of adversity, a so-called "support provider" can buffer a person against the debilitating effects of stress and also help that person thrive. First, the support provider can offer a safe haven where the person feels sheltered and able to free him or herself of burdens. Once the person feels safe, the support provider can offer fortification, which involves helping to develop the specific strengths and abilities relevant to coping with the adversity, Feeney said.

As the setback continues, the support provider can motivate and help the person get up and stay in the game by using strengths to rebuild, problem-solve or cope with the adversity in a positive way, she explained. Finally, the support provider can help the person redefine the adversity as something that isn't threatening, but rather is a catalyst for positive change.

For instance, a man may feel undesirable if he goes through an unwanted divorce. His friends can help set up a safe haven and listen to the man's challenges. But they can also remind him that divorce is common and tell him that he's handsome and funny. Redefining the divorce as a positive change may help the individual move forward and meet a new partner, the researchers said.

"Together, we refer to this as providing a source of strength (SOS) for thriving through adversity," Feeney said.

The study helps reveal when and in what ways close relationships can bring out the best in people, said Eli Finkel, a professor of psychology at Northwestern University in Evanston, Illinois, who was not involved in the study. [6 Scientific Tips for a Successful Marriage]

"It adds important insights regarding situations in which people are struggling and look to their loved ones for support," Finkel told Live Science. "But the even larger contribution of this work is that it provides an insightful and compelling analysis of how loved ones can help us in our pursuit of personal growth."

Ordinary thriving

Even when setbacks aren't on the horizon, support providers can foster thriving in others. People who act as a "relational catalyst" can embrace opportunities for growth in everyday life, Feeney said. To start, they can encourage the person to leave his or her comfort zone and try new activities or pursue a goal.

If a person is concerned by real or imagined difficulties, the support provider can help them focus on the positive aspects and point out that even if an endeavor doesn't work out, its pursuit may provide space for growth.

"This also includes assisting the person in recognizing opportunities that might otherwise be missed," Feeney said.

The support provider can help the person find an attainable goal and create a strategy to pursue it. Friends who are available, but not overly intrusive, can then celebrate the person's successes, such as getting a degree, or respond in a sensitive way to failures or setbacks, such as not getting a job promotion.

Yet these supporters can also overstep their bounds, the researchers said. If they make a person feel weak, needy or inadequate, or even guilty or indebted, it can be hard for the person to thrive. Feeney named a variety of other ways a supporter can demean recipients, such as by making them feel like a burden, discounting their problems or accomplishments, blaming them for their misfortunes, restricting their independence, or taking too much control over the situation.

"We suggest that unresponsive and insensitive support behaviors will undermine thriving because they promote either overdependence or under-dependence in relationships," she said.

Science of relationships

The new study draws on findings from about 400 studies that examined close relationships, including many written by Feeney and her colleague Nancy Collins, a professor in the department of psychological and brain sciences at the University of California, Santa Barbara, over the past 15 years.

"It blends their best ideas from that era with a slew of new insights to generate a truly major contribution to the science of relationships and human thriving," Finkel said.

The review's framework may provide a foundation for developing relationship-based interventions for families, and training for mentors who work to help others thrive, Feeney said. People can thrive if they have supporters who have their backs in both good times and bad, she said.

"Building strong close relationships is a virtual prerequisite for human flourishing," Finkel said. "Whether we're seeking to persevere through adversity or to stretch ourselves in challenging new directions, support from our loved ones is crucial for success."

The study was published online today (Aug. 29) in the journal Personality and Social Psychology Review.

Follow Laura Geggel on Twitter @LauraGeggel and Google+. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.