When you’re a teenager, you’re surrounded by new friends, new classmates and maybe even new romances.

All of that excitement can make it difficult to identify which relationships are the most important to maintain. But as you head into your 20s and 30s, being strategic and thoughtful about who you stay in touch with will benefit you in many ways.

Sure, social media in today’s world has made it easier to stay connected with people 24/7. But based on experience as a therapist who mostly works with millennials, young adults are feeling lonelier and more disconnected than ever before.

In fact, a 2018 study from Cigna found that Generation Z (ages 18 to 22) and millennials (ages 23 to 37) are lonelier and claim to be in worse health than older generations.

According to survey data from more than 20,000 Americans (ages 18 and older), those who engaged in frequent meaningful in-person interactions had lower loneliness scores than those who rarely interacted with others face-to-face.

All of that points to a hard truth about adulthood: As you grow older, many people will enter your life, but the people who will truly be there for you during difficult times — in both your professional and personal life — will be in much shorter supply.

To have a strong support system when you’re much older, here are the five relationships to invest in when you’re in your 20s and 30s:

1. The old friend

We all need connections from our past to keep us grounded, which is why it’s important to maintain a relationship with someone who is a reminder of our younger selves.

This might be your best friend from middle school. Or your close buddy from college who moved to a different city after graduation. It might even be a sibling or close cousin.

An old friend not only sees you through your growth spurts and bad haircuts, but through your emotional tribulations as well. This person is less likely to let you down when you need a shoulder to lean on, provided that you both make an effort to nurture the relationship.

Of course, life happens and you might end up falling out of touch for months or even years. But you can always pick up the phone or schedule a Skype session to catch up.

2. The professional mentor

My patients often ask me for career advice: “I applied for this job at Google, but I haven’t heard from them in weeks. How do I get in touch with someone at the company?”

As a therapist (and not a career counselor), I can’t always give them advice on what career moves to make next. That’s why it’s important to build a professional relationship with a mentor who you trust and respect.

This should be someone in your field of work who has more years of experience, can open doors to new opportunities and give you the push you need to advance in your career.

You might have to be the main driver of this relationship — and that’s okay. Keep them in the loop about where you are in your career, ask them how they’re doing from time to time and always express your gratitude for their guidance.

3. The parental figure

people don’t realize how important it is to maintain a strong bond with their parents until they’re much older.

I’ve had so many patients whose problems could be traced back to their relationships with their parents. One suffered from daily guilt and regret from not telling her mother how much she loved and appreciated her while she was still alive.

If you’re lucky enough that your parents are still alive, it doesn’t hurt to strengthen that bond and get to know them better. Look after them (as they once did for you), make them feel loved and allow them to be a supporting anchor in your life.

If your parents aren’t around, you can still cultivate a relationship with an older person who is similar to a parental figure.

4. The physician

So many of my patients enter adulthood knowing very little about what’s going on with their body. And as they grow older, they start to stress about their symptoms and illnesses that probably could have been prevented.

According to a study from the, people who have good relationships with their physicians tend to be more active in their own healthcare. That means they’re more likely to monitor their own conditions, exercise and make healthy lifestyle choices.

At the end of the day, it’s your body, mind and life. Knowing that you’re taking responsibility for your health will make you feel more relaxed and confident.

Finding the right doctor won’t happen overnight. It may take a lot of time, research and shopping around. But ultimately, you should find someone who takes his or her time talking to you, engages you in the decision-making process, makes you feel comfortable and can be easily reached.

5. Yourself

I saved the most important for last. Having a strong relationship with yourself means seeking help when you need it and learning the tools and techniques to help manage life’s ups and downs.

The way you think about and treat yourself plays a vital role in your physical and mental well-being.All the other essential relationships can’t thrive if you don’t have a strong sense of who you are.

I often tell my patients to spend a few hours alone every week doing activities that brings them joy. I also encourage them to keep a journal and write in it daily. Taking time to reflect on your thoughts and feelings is a powerful way to get to know yourself better.

Tess Brigham is a San Francisco-based psychotherapist and certified life coach. She has more than 10 years of experience in the field and primarily works with millennials and parents of millennials.

Written by Tess Brigham, Contributor at CNBC:

https://www.cnbc.com/2019/08/06/5-types-of-relationships-to-invest-in-when-youre-in-your-20s-and-30s.html?source=facebook%7Cmain&fbclid=IwAR0w6ziNleld96DpzgKOyy0Be9LlXiX2hKQL6zr_4z_n0Xs2gG1IcXqMKpA