Who would have thought that movies could teach us about happiness? When my children begged me to see the new Trolls movie, I was a bit shocked, however one of the movie’s main lessons is how vital friends are in boosting our mood and making us feel happier.

Poppy, the troll princess, is perpetually gleeful and optimistic. She leads the other trolls in singing, dancing and hugging all day long. One troll does not buy into all this happiness. Poppy is constantly trying to get Branch to smile and join the rest of the group in being cheerful all day. Throughout their adventures to protect the trolls from their enemies (called Bergens), we learn that when Branch was a young boy, his grandmother was taken away by a Bergen. He blamed himself for her disappearance because she was distracted by his beautiful singing and did not see the monster approaching. He became sad, losing his color and ability to feel joy.

Towards the end of the movie, Poppy faces a challenging moment and loses hope. As she begins to turn grey, Branch knows that he has the power to cheer her up. He sings an inspiring, loving song. Much to Poppy’s surprise, Branch comes full circle and helps her return to her happy self. The two trolls then hug each other and their color returns, brighter than ever.

This powerful scene shows how friends can make us feel better and pull us out of our darkest moments. Here’s what we can learn about positive peer pressure.

How positive peer pressure works

We often hear about the many negative aspects of peer pressure, but there is a flip side to it if harnessed in the right way. As we see in the movie, friends can play a major role in building our happiness. Positive peer pressure occurs when friends try to influence other children or teens to do something positive, proactive, or productive. This encouragement improves the behavior and attitude of the individual, leading to positive change and growth.

Positive peer pressure can influence both thoughts and actions. When children are inspired to think more positively about themselves, their entire life improves. They can overcome negative self-talk and low self-esteem, allowing them to live happier, more productive lives.

Children look to imitate their peers from an early age. Studies show that happiness is contagious, so we can hope that our children surround themselves with cheerful friends. A Harvard Medical School study found that one person’s happiness spreads through their social group even up to three degrees of separation, and that this effect can last as long as a year. They actually determined that having a happy friend can improve our likelihood of being happy by 15%.

How relationships impact our happiness

Poppy was persistent in trying to cheer up Branch throughout the movie. Eventually, her hard work paid off so much so that he found happiness, and then channeled it to make Poppy feel better as well. Scientific research in the world of positive psychology indicates that one of the most critical components of happiness is the relationships we have with others.

Happiness experts Ed Diener and Martin Seligman compared the happiest to the least happy people. Their research found that the happiest individuals were highly social and had the strongest relationships. Actually, good social relationships were necessary for people to feel happy.

Additionally, research led by Robert Waldinger at Harvard University that followed the lives of people for more than 75 years concluded that relationships are the key to a happier life. The happiest and healthiest participants in the study maintained close, intimate relationships. According to Waldinger, the people who tend to be more isolated than they want to be from others are less happy, their health declines earlier, and they live shorter lives than people who are connected to others. He also explained that it’s not about how many friends we have, but the quality and stability of those relationships throughout our lives that really matters.

Why friends can help reduce depression

Sadly, depression is one of the most common mental health issues in the United States. According to the Anxiety and Depression Association of America, two out of 100 young children and eight out of 100 teens may have serious depression, causing them to feel discouraged, sad, hopeless, unmotivated or disinterested in life. Additionally, the National Survey on Drug Use and Health in the United States indicated that 10.7% of 12- to 17-year-olds had at least one major depressive episode during 2013 alone.

One of the best ways for our children to overcome feeling blue is to spend time with their friends. Because of positive peer pressure, a caring, upbeat friend can help improve their mood. In a recent study, scientists found that happy friends can help teenagers beat depression.

Feedback from 2,000 American high school students was analyzed to investigate whether the moods of students influenced one another and if this could impact levels of depression among teens. They found that depression does not spread among peers, but a healthy mood (not feeling depressed) actually does. By surrounding themselves with friends—especially happy ones—teens can significantly reduce their risk of developing depression, and improve their ability to recover from it.

Positive friendships were much more effective than using antidepressants.

So, what does this mean for parents trying to raise happy kids?

It is critical that we pay attention to the type of friends our children are attracted to. If there are any red flags, we can redirect them to more positive choices—friends they can look up to and who inspire them to become the best person they can be and professionals who can help as well. We can also instill the importance of building positive relationships by doing the same in our own lives.

Finally, we can build a positive community for our children from a young age by participating in group activities such as playdates, team sports, community service projects, neighborhood gatherings, and other relationship-building events.